For Travis Warren, playtime on the iPhone is over.His company, WhippleHill, which serves private schools across the country, spent the last six months working on an iPhone app that hooks into its Web-based services. WhippleHill plans to roll out the new iPhone app to some 350 schools next month."It took a long time to develop the app," says Warren, president and founder of WhippleHill. "We got lucky that our competitors aren't on the iPhone yet."[ Call it a coming of age as more iPhone business apps emerge, reports CIO. | Even the iPod Touch is an iPod of war. ]The race to iPhone apps that provide real services\u2014not just simple tools or cool games\u2014has taken on Triple Crown momentum. Web service providers are looking beyond the iPhone's Safari browser for accessing their services, setting their sights on an iPhone client app delivered over the App Store.Excitement bubbled when Apple announced the iPhone 3.0 update earlier this year; iPhone 3.0 will be available to users later this month. The new version lets SaaS providers charge for their services over the iPhone. "We're heading into the age of micro SaaS," says Gartner analyst Ken Dulaney.But first, a warning: It's not easy building an iPhone app that taps into backend Web services. Just ask WhippleHill's Warren, who had to find creative ways to get his iPhone app project off the ground and then wade through technical hoops to bring it to market.How to build an iPhone app for freeWhippleHill sells services to private schools so that teachers, administrators, coaches, parents and students can log in and get attendance records, contacts, schedules, progress reports and more. Twelve of WhippleHill's 15 advisory schools said they were willing to pay a $2,000 premium on their annual subscriptions to be able to tap into their dashboards over the iPhone. Yet this still wasn't enough to justify the high cost of building an iPhone app, Warren says.So Warren sought cheaper software development with an Indian outsourcer with whom WhippleHill had contracted with in the past. But the outsourcer didn't have experience with the iPhone SDK, and thus tried to push WhippleHill toward a browser-based solution\u2014that is, iPhone users on Safari would be routed to a mobile site with big links. "They didn't really get it," Warren says.Warren's search for alternate options led him to a bunch of Stanford University students who had formed a company, TerribyClever. The students had written an award-winning iPhone app called iStanford (and later, Duke Mobile) that a Time Magazine story called a rival to Facebook Mobile.TerriblyClever's business plan is to sell the platform to other universities in big licensing deals. Warren called TerriblyClever CEO and Founder Kayvon Beykpour with a proposition: "I told them I couldn't get them six-figure deals," Warren says, "but if they could tie into our system for free, I could get them a revenue stream. Maybe a half-million for them, a half-million for me."A partnership was formed, and TerriblyClever began the complicated task of porting its iPhone app platform to WhippleHill's backend system. The process was anything but smooth.The long, twisted road to the iPhoneFor starters, TerriblyClever had to re-engineer the access and authentication layers used by WhippleHill's servers. "We thought that our Web services, as they'd been designed, were going to cut it, that we'd simple connect the pieces," Warren says. "By the time it was done, we basically re-wrote our Web services."WhippleHill's API wasn't poorly designed; in fact, Beykpour was very impressed, he says. Nevertheless, a lot of custom coding needed to be done. "We had to reroute all of the inner workings," Beykpour says. The WhippleHill iPhone app needed to tap into all of WhippleHill's services while controlling access for some 30 different user roles. It had to ensure that all of the business rules governing the data and drilldowns were supported.Development dragged on as Beykpour and his team of engineers divided their time between WhippleHill's iPhone app development, improvements to their platform, and class finals.Even big tech companies face similar technical challenges. A simple iPhone app for expense management might be easy enough to develop, says Chuck Dietrich, vice president of mobile at Salesforce.com, "but it's challenging to build an application framework that can become any application based on messages coming down from the cloud."(Salesforce.com should know: This SaaS leader was one of the first providers to deliver an iPhone app that accesses its Web services. The iPhone app has been downloaded more than 80,000 times, and Salesforce.com now offers a platform for others to create an iPhone app.)On the upside, TerriblyClever was able to speed things along thanks to a close relationship with Apple, says Warren.Beykpour is quick to point out that TerriblyClever's iStanford and iPhone app platform aren't officially endorsed by Apple. Apple, of course, is notorious for its indifferent attitude toward third-party developers, such as rejecting iPhone apps that it deems to contain objectionable content\u2014one rejected app contained the Kama Sutra\u2014from being sold on its App Store.But the relationship between Silicon Valley icons Apple and Stanford University, 15 miles away, has always been tight. CEO Steve Jobs delivered a commencement speech to Stanford graduates a few years ago. Indeed, iStanford's early development was influenced by Apple. "A lot of our brainstorming was done with certain people from Apple who were connected to Stanford," Beykpour says.The race to the App Store heats upWhippleHill's iPhone app made it to two of its test schools this week and will be rolled out to all schools next month. That's good timing, since some schools plan to hand out iPod Touchs to teachers to take attendance. This data can go right into WhippleHill's system."I'm amazed at the penetration of the iPhone," Warren says. "I have meetings with [school] boards and I'd say at least 60 percent of the people have iPhones."While background processing on the iPhone isn't here yet, iPhone 3.0 released earlier this year supports alert notifications. And Warren hopes to add alerts for iPhone-toting parents, making it harder than ever for kids to cut class.Apple will eventually bring background processing to the iPhone, enabling non-running iPhone apps to receive updates automatically. Gartner's Dulaney suspects some SaaS providers are waiting for Apple to deliver this feature, as well as the ability to charge customers over the iPhone, before coming out with their iPhone app.WhippleHill's Warren, though, says he's glad he didn't wait. On the contrary, if he had to do it again, he says, he would have scaled down the iPhone app to get it out the door in less than six months. "We implemented four feature sets," he says. "I would have implemented one, gotten it up quicker, and then let my users dictate where to go with it."Are you working on an iPhone app? Dealing with support issues? Send me an email at email@example.com. Or follow me on Twitter @kaneshige. Follow everything from CIO.com on Twitter @CIOonline.