First off, I recommend against using downloaded footage, especially fansubs, in AMV making. If it is available on DVD, use that instead since the quality will be better and the
guides available here are generally written with using DVDs in mind.
For XVID/DIVX AVI files, you have a couple of options:
1 - using AviSynth and VirtualDub/Mod, convert them into either Uncompressed RGB, Huffyuv, or Lagarith AVI (use DirectShowSource()).
http://www.animemusicvideos.org/guides/ ... meth1.html
2 - using AviSynth, frameserve the video directly into Premiere (import the AVS file).
http://www.animemusicvideos.org/guides/ ... ocId295338
For WMV files, you can do the same things as XVID/DIVX AVI files and one other option:
3 - drop it into Windows Movie Maker 2 and convert them into DV AVI.
http://www.animemusicvideos.org/guides/ ... xport.html Whether you continue to convert the files to Huffyuv (or other lossless AVI) as in the guide is your choice; Premiere will load DV AVI files.