I read in an earlier post that you folks were evaluating which codecs to support with the transcoding feature. I would imagine that the most important option for most web apps would be to convert from the various primaries (AVI, MPG, MOV) to Flash Video (FLV).
Also, will there be a feature to generate a preview image from the transcoded file (similar to the initial still shot visible in the YouTube player)?
A final thought...please keep transcoding cheap! Anybody who plans on having any significant amount of video media uploaded and converted would have to think long and hard about just using their own server to batch the jobs if the cost is too steep. It would be great if it was priced as affordably as the other aspects of your service.