An app to play AVI & MKV files..?

hi there

i currently have an Android Phone (the Samsung Galaxy Apollo i5800) and i found the phone to be quite useful in my everyday life. but secretly i am a lover and admirer of the iPhone and its apps and uses.

i have several Divx files (in AVI container) and MKV files as well. now, i'm aware that officially the iPhone (3GS and 4) cannot play these said files but i have heard and read that an app will be able to.

i would like to know which app is this please? this would be a turning point in finally deciding to buy an iPhone again...

thanks.