What's the matter? Open the movie with VirtualDub, select Video__Compression, choose the DivX codec (you need a registered version of DivX, oy you might use Xvid) and Configure it. If the audio is already OK you can keep Audio__Direct Stream Copy, otherwise you have to set Audio__Full Processing Mode and to set an audio compression, too. Codecs' bitrate calculators are used to choose the right bitrate settings for those codecs, to achieve the size you want.