The iPhone has now been out for awhile and widgets are appearing nearly everyday, some more relevant than others. Below are the most promising of the bunch so far.
SandBox TV made just for iPhones. Soon the iPhone version of sandboxtv will match all channels on sandboxtv.com
Combine up to ten RSS feeds into a new, custom feed that you can easily output to your iPhone.
Share your personal videos, privately or publicly.
iTweet.net allows use for Twitter on their iPhone.