The Google Operating System has blogged about a startup called FriendFeed, which aims to let you grab the data you like sharing with friends (such as photos) from all the places you keep it online, so you can easily share it via one feed.
"FriendFeed ....lets you enter your usernames from different sites and combines all the data in a single feed that can be easily shared with someone. You can also invite your friends and subscribe to their data. The service makes a lot of sense if you use it from a social network like Facebook, so FriendFeed has a Facebook application."
FriendFeed is in invitation-only beta mode at the moment, you can request an invitation here.
Keep Track of Your Friends' Shared Items [Google Operating System Blog]