In function, texting treads a fine line between those two communication capabilities, essentially serving as a basic form of e-mail for even the simplest of today's cell phones. Text messaging relies on a decades-old technology called SMS--Short Message Service--that's used to relay brief messages (usually no more than 160 characters, equivalent to a couple of average-length sentences).

Teens typically use texting for trivial cell-to-cell communication ("WHERE R U?", "AT THE MALL!"). But savvy travelers can leverage SMS for a whole lot more. Let your thumbs do a little walking (over your phone's keypad) and you can check flight status, update your calendar, track a package, check your bank balance, and get driving directions to almost anywhere.

You don't even always need your thumbs: Some services let you send messages and retrieve information using just your voice. Best of all, most of these text-messaging marvels cost nothing to use--though you'll want to check with your carrier to see how many messages (if any) are allowed as part of your monthly plan.

1. Remember Your Appointments and Schedule New Ones

Can't remember what time your next meeting takes place? If you're a Google Calendar user, you can find out in a flash: Just send a message with the word "next" to GVENT (dial 48368) and you'll get back the time and details of your next scheduled event. Send "day" for a full list of today's appointments and "nday" for tomorrow's.

Google Calendar also lets you add new events via SMS--and you can use plain English to do it. For example: "Lunch with Joe at Panera Bread tomorrow at noon." Shoot a message like that to GVENT, and Google will add it to your calendar with all the appropriate details.

Finally, you can configure Google Calendar to send automatic reminders in advance of an event. For any existing entry, click Edit Event Details, then Add a Reminder. Choose SMS from the list of options, and then specify how far in advance of the event the notification should arrive. Before you can leverage Google Calendar's SMS features, you have to configure it for use with your phone. In your Web browser, open Google Calendar and click the Settings link, then choose Mobile Setup. Follow the simple cues to enable cell-phone notifications, and you're all set. Of course, Google Calendar isn't the only game in cyberspace. Services like PingMe and Sandy can deliver notifications to your phone and process new reminders that you send from it. And Kwiry helps you remember things you're supposed to do by routing text messages created on your phone to your e-mail inbox.