There've gotta be some free utils out there to convert other vid formats to m4p.

I just googled "convert video to ipod format" and came up with something called "Videora".
Don't know if it's any good.
Might be worth while to check the ilounge.com forums - I'm guessing they've got a whole bunch of recommendations.
(I stopped looking when I found the software I already had for video editing did a good job with it.

As RReuscher said, conversion takes a while as it is CPU intensive. I think a 22 minute Futurara episode took about 30 minutes to render in Ulead - but I wasn't timing it (Athlon FX51 CPU with 2 gig RAM).
If you end up getting heavily into video on the ipod, you'll definately wanna check out that .264 hardware he mentions.