barlings007, In order to be able to play videos on your PPC you need movies that are specially made for the ppc.
one of the requirements is that the video has a maximum resolution of 320x240 or smaller. The bitrate must not exceed a certain amount (this differs for each ppc) as a rule of thumb the bitrate should be BELOW 300kilobits/s. there is no easy way of guessing or reading the bitrate accuratly but in general here are a couple of examples: a 40 to 50 minutes long show should have a size of max. 70MB a full feature movie should have a size of max 200MB
The figures above are not a rule but just something that indicates that it's reasonable to assume the movie is optimized for PPC-playback.
-When playing .avi's you should always use PocketMVP and not windows media player as most avi's are nowadays containing divx and this cannot be played correctly by WMP.
-If what you are trying to play are movies you downloaded from kazaa they are probably not optimized for playing on the ppc
If you want to know more about making PPC-compatible movies and stuff like that you should search a bit on the forum as there have been several threads on this.
Have a read here:
This guide
This Thread
This thread
This site