MicrostockGroup

Hi video people!
I do a bit of 3d stuff and was thinking about trying a couple of animated videos. I am a total beginner at this.
My question is about which formats and at what resolution I should be outputting the animations at to get them onto the sites available at the largest resolutions they sell.
Is there something that's the equivalent of the jpeg (a standard that will be accepted across all the stock sites) or do they all ask for different formats (.avi for some, .mov for otehrs etc.)
Any help would be greatly appreciated.

thanks very much, just the info I was after (hearted)