Is there a video camera app i can download that will work for the 3rd generation iphone?

i tried buying one and it said it's not supported. is there one that will work for my iphone? my iphone is the latest one that came out right before the new 4g iphones. thank you!
Update: oh i was told it was the 3GS but i guess its the one before that. :/ there an app i can download anyways for video camera?
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