You shouldn't have to do much conversion, from the Nokia USA site:

Video playback file formats: .mp4, .avi, .wmv, .3gp; codecs: H.264, MPEG-4, Xvid, WMV, H.263
Video streaming: H.264, MPEG-4, Xvid, WMV, H.263 in .avi, .mp4, .wmv, .asf and .3gp containers

That pretty much covers everything you will run into. If you find a video you can't play, there's an extra codecs pack in the software repository that's free.

Here are the links, if you're interested: http://www.nokiausa.com/find-product...ions#video-vsp

http://maemo.org/downloads/product/M...oders-support/