You can use the iPhone (browser bookmark to home screen), email, your tweets show up here. Maybe check out Tools up by the Search box for others....
- Gabe Taviano
Rochelle's pretty much right. Twhirl also has a FF client, and there's Nambu and BuddyFeed on the iPhone, but the main site and the iphone version of it that Gabe and Rochelle mentioned are really the best interfaces.
- Jandy, ConcertMaven of FF