Mac OS X only: Inspired by previously mentioned TweetMyPC, free application TweetMyMac remote controls your Mac from anywhere you can access Twitter, allowing you to restart and shutdown your computer, take a screenshot, open a torrent and more.
To get started using TweetMyMac, you'll need to sign up for a new Twitter account dedicated specifically to controlling your Mac, then follow your main Twitter account from your new dedicated account. (Note: You should only follow that one account from your TweetMyMac Twitter account—unless you want to give random people the ability to remotely control your Mac. You'll probably also want to protect your updates.)
Once you've set up your dedicated Twitter account, installed TweetMyMac, and set it up with your new Twitter account, you're ready to execute some commands.
Command Purpose shutdown Shutdown your Mac. Will NOT save any open files. restart Restart your Mac. Will NOT save any open files. logout Logout of your Mac. Will NOT save any open files. sleep Sleep your Mac. ip Get your Mac's external IP address. Your Mac will reply with it's current IP. isight Snap an image from your Mac's iSight camera. Your Mac will reply with the picture posted on TwitPic. screenshot Get a screenshot of your Mac. Your Mac will reply with the picture posted on TwitPic. say [phrase]Your Mac will speak the phrase in the default voice. torrent [torrent URL]Your Mac will download the torrent and open it in the default torrent client. [URL]Your Mac will open any URL it is sent. %[command]Your Mac will execute the custom shell command. Note: this is disabled by default for security and must be enabled in the options to use.
I'm particularly partial to the torrent command, considering it allows you to start a BitTorrent download from any mobile device capable of copying and pasting a URL. (Does this mean Apple will have to reject Twitter apps now, too?)
TweetMyMac is freeware, Mac OS X only. For a Windows alternative, check out previously mentioned TweetMyPC.