E-Commerce Service Yahoo Small Business

You'd be surprised at some of the sophisticated things being done with the simple e-commerce service at Yahoo Small Business. Yahoo provides everything from templates and wizards to credit-card processing and sales-tax collection. If you sell less than 50,000 units, this is definitely one of the easiest and quickest ways to go online. Even better: A small army of third-party developers stands ready to create Web designs that work specifically with the service. ($40/month and up, plus transaction fees)

E-Mail Thunderbird

If you have Microsoft Office, you already have Outlook, the industry-standard e-mail app. But if you're looking to save a buck and still get most of Outlook's features, Thunderbird is a capable, free alternative. Message tagging and a speedy, integratedsearch system actually offer a few improvements over off-the-rack Outlook. (free)

Yahoo Zimbra Desktop

Another interesting, non-Outlook e-mail option is Zimbra Desktop, which Yahoo acquired earlier this year. In simple terms, the Zimbra Desktop is an offline version of Zimbra's capable Web-based e-mail manager. It includes everything a small-business user needs: a contact manager, an impressive calendar, a to-do list, and even a simple, integrated document manager for quick note-taking. (free)

E-Mail Marketing Topica

Don't call it spam: Communicating via e-mail with your customers is cool, as long as they opt in. Topica has been in the e-mail marketing/mailing-list game for years, and most spam filters are pretty kind to messages that are sent through its service. Topica is also one of the most affordable of such e-mail marketing platforms that you can find on the Web--and it sure beats running a mailing list server yourself. ($50 per month and up depending on e-mail volume)

Instant Messaging Pidgin

You don't have to run four different instant-messaging applications just to communicate with your clients and with everyone in your office. Multiprotocol software like Pidgin allows you to communicate with users across more than a dozen IM services: Not just AIM, ICQ, and other biggies, but also lesser-known ones like Gadu-Gadu (it's Polish) and Zephyr. Trillian is similar, but it supports fewer services. (free)

Invoicing Zoho Invoice

Don't need a full-fledged accounting app like QuickBooks? Zoho Invoice is a near-perfect Web-based solution for managing simple billing needs. Create and manage customer accounts, build invoices, and then print or e-mail them with a mouse click. You can also tie in your use of Invoice with Zoho's other, extra-cost business services. See our full review of Zoho Invoice. (free to $35 per month depending on invoice quantity)

Mobile Device Remote Access SoonR Desktop

It's one thing to be stuck in an airport without access to a critical file back at the office, but what if you don't even have access to a computer? Enter SoonR, which lets you snag files from your PC or Mac via a mobile phone. SoonR isn't built for serious data transfer needs--but it just might get you out of a jam when it counts. (free)

Office Suite Microsoft Office

Like it or not, any business, big or small, probably needs at least one copy of Microsoft Office somewhere in the building. All of the suite's applications are simply too close to being industry standards to ignore. It can be pricey, but you likely needn't worry about upgrading to the latest version--anything produced since the turn of the century should do. ($85 to $400 per user, depending on version)

OpenOffice.org

Don't want to fork over beaucoup bucks for Office? We can't blame you--and this alternative suite will work for 95 percent of your productivity needs. OpenOffice.org is mostly compatible with Microsoft Office, and operations are similar enough that any Microsoft user should have no trouble using it. The big three apps--word processor, spreadsheet, and presentation tool--are all here, along with a simple database and drawing tool. One caveat: OpenOffice has trouble with Office 2007 files; but the imminent new version, OpenOffice 3, is said to remedy that limitation. (free)

Project Management Basecamp

Build complicated project timelines, to-do lists, and message boards, and share files among your team members-all via one simple-to-use Web tool. Basecamp can keep all your workers on task while letting everyone else know what other team members are up to. It can even track project time on a per-member basis, for creating detailed billing and reports when the job is done. ($24 to $149 per month, depending on number of projects managed)

Remote Access/Syncing LogMeIn

If all you need is occasional access to a single PC that isn't within walking distance, you can get by with this simple remote-access tool. LogMeIn lets you quickly connect to your office computer to grab a file or check an application you don't have on your laptop, all via any computer with a Web browser. (free to $20 per month)

Syncplicity

If you regularly use more than one computer, keeping track of which machine has which version of which report can get a little confusing. The solution: Synchronize the PCs so you can ensure they're all up-to-the-minute, while protecting yourself in the event you made different changes to the same file on more than one PC. Unlike most traditional sync software, Syncplicity works over the Web, so you can sync from anywhere. (free for 2GB limit, to $10 per month for 40GB limit)