TCPMP does not support skinning yet. From what I have read at Corecodec.com they are planning to release version 1.0 in the near future and that capability will probably be included.
The plugins add the capability to play video and audio formats other than included in the main program. Picard has also released an experimental plugin to play AVC encoded files.
Check out the lastest test release with plugins at:
http://picard.exceed.hu/tcpmp/test/
This page also includes a sort of bare bones player for a windows PC.