is there anywhere i can get a portable wmp codec for mpeg-4? or avi?

 

No, you need to install a program called betaplayer. This is a great media player for pocket pc. It can play divx, xvid, mpeg and many other formats. http://betaplayer.corecodec.org/

   

As far as I'm aware there are no extra codecs available for WMP. WMP10 Mobile supports Microsoft MPEG-4 V2 & V3 and ISO MPEG-4 V1 in ASF(WMV) files only, if you are looking to play DivX,XviD,H.263,H.264 etc. then Betaplayer is really the only worthwhile choice.

There is no such thing as an AVI codec because it's not an encoded format merely a file container that can store encoded video, audio, annotations, subtitles etc inside of it, the term is either demultiplexer or splitter. All pretty irrelevant stuff though as WMP Mobile does not support AVI and by the looks of things never will.