I gave it a test run on my iPhone and it works quite nicely.  I am of course using my wifi because the Edge network is unbearably slow, but it displays the content very well in landscape or portrait mode.   I did notice one quirk though that I hadn’t noticed with other sites yet, and that is during the login it really slowed the iPhone down.  I literally typed my entire username on the keypad befor it started to type on the screen.  Then after that it did about 1 letter a second till the word was done.  May be totally unrelated to digg, but that is the only site it has happened on so far.

Head over to digg on your iPhone at http://www.digg.com/iphone

Happy digging!