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

iPhone link is http://www.friendfeed.com/iphone - forgot that, sorry! - Gabe Taviano

Not so many. You might want to try out http://www.frienddeck.com/ or http://www.alertthingy.com/. On a phone, try fftogo.com or friendfeed.com/iphone. - Rochelle

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