Even better, it does so wirelessly: You can beam print jobs to nearly any printer on your network, so long as your iPhone is connected via Wi-Fi to that same network. It also supports shared Macintosh printers.
I say "nearly any printer" because Print Magic has been hit-and-miss in my home office.
Until the latest version (1.1) was released just yesterday, it would only churn out blank pages on my Brother HL-2170W. Now it works like a champ with that model, but can't seem to communicate with a Brother MFC-440CN. (It detects it, but test pages don't go through.)
Needless to say, your mileage may vary. It's too bad developer Wellala doesn't offer some kind of trial version, as I'd hate to drop $6.99 on this app and then discover it doesn't support my printer(s). Update: A Wellala rep says a "printer test" version of Print Magic is imminent! Look for it in about two weeks.
Still, when it works, it's a dream come true. To print text, just copy it, then fire up the app. Same goes for Web pages: copy the URL, run the app. As for photos, you can choose one from your library right from within Print Magic.
The app gives you a choice of output sizes and number of copies (1-5 or 10).
Though still a little buggy, Print Magic is insanely handy, and definitely worth adding to your iPhone app arsenal.