What are Winamp's video channels like? That's kind of like asking
"How do I view QuickTime's Content Guide in Windows Meda Player?" though. It may not be possible without Winamp.
m3u files aren't streaming files. They're just playlists. iTunes, QuickTime, or the Finder can play them. If you had tried you would have found that out yourself.
They open in iTunes by default I think.
If you're trying to view WMV content, you'll need to get
flip4mac.