I may be the last one to the party here, because I noticed a lot of you guys using instagram to share your pictures on twitter! This is my favorite camera iphone app for 2 reasons:
- this is the first app I have ever found that gives you rounded corners on the finished pic ( I love love LOVE rounded corners and wish iphoto gave me that option, or any software for that matter)
- It is easy to use and has integration for facebook, twitter, 4square etc

Here is my starting picture I pulled from existing photos on my phone:
And here are some after I applied filters and saved !

Neat Majeat! It is a Free download in the app store!