need help converting mpg to divx

[DannyBoyZ]

here is the problem,i have a 1 gig mpg filee loaded into virtual dub,followed the tutorial on the left side there <--
and when i pick the slow divx codec it doesn't do anything at all,when i pick the fast divx codec i get a massive ai file,like 3 freaking gigs????
how can I do this properly and/or is there another program to convert mpg to divx?
thanks

[Baldrick]

You can checkout http://www.vidomi.com

But it should work with Virutaldub.