Qxtream is a mix of a download manager for Megaupload and a video player that allows you to watch any video hosted in Megaupload wihtout having to download it and with no codec problems.
It is very easy to use. You only have to insert the link of the video file you want to watch or access one of the featured in their catalog, wait a few seconds and you'll be watching the video instantaneously, because you won't have to download it before watching it.
Qxtream is a very useful program if you don't want to wait until the video is totally downloaded to view it or if your HD is full and you can't download big files.
You'll need a Megaupload Premium account