You can convert wmv to avi buy using Forty-Two DVDVX Plus $15
http://www.kaisakura.com/Forty-Two_DVDVX_Plus.html
Then use iMovie which came with your Mac for editing.
A cheap encoder is ffmpegX ($15)
http://homepage.mac.com/major4/
FinalCut Pro for editing
http://www.apple.com/finalcutpro/
Then to make MPGs and other web formats
http://www.discreet.com/products/cleaner/cleaner6/
MediaEdit Pro has Paint & Draw Tools and is only $40.
http://www.macxware.com/candypress/S...p?idproduct=23
For splitting and joining movies.
http://www.biermann.org/philipp/mpegcut/
BTW, WMV files suck. You can't easily protect them.