Set Up YouTube How You Want It
You can browse YouTube in several ways on the iPhone. Default options include the Featured and Most Viewed lists from YouTube as well as your YouTube bookmarks and search. All these are displayed as buttons along the bottom of the YouTube screen, along with a More button that includes Most Recent, Top Rated, and your history.
As with the iPod application, you can click an Edit button in the top-right corner of the More screen to edit the four buttons at the bottom of the screen, making it just a little easier to browse content the way you want.