We've now gotten a few reports and some screenshots of yet more new functionality in iPhone 3.0 Beta 3.
First is "merge". If you already have bookmarks, contacts, or other data on your iPhone (for example, if you synced it over via iTunes) and you enable MobileMe, a menu will slide up asking if you want to merge the data, not merge (i.e. replace), or cancel.
Next are "Publishing to MobileMe", which shows a direct upload status bar, and new options to view published items on MobileMe, or "tell a friend" (via MMS?).