I do the same thing. I put my AVI in Premier, touch it up, export it with AviSynth, convert it to MPG2 with TMPTEnc, and then use Flask to convert it to DivX. You can fit over an hour of video in near DVD quality using the DivX codec... very nice! I just hope it's going to be around in 5 years.

Let me know if you have more detailed questions about this process.