Your very welcome Dnvr. Also, I sort of forgot to mention this but if you go to File and select Play URL and type in "linein://" the plugin will respond to your mic (if you have one). And then if you right click the speaker in the notificaion area and hit recording options you can right click on "stereo mix" and enable it (do the same to disable your mic). Then the plugin is reacting to other sources of sound from your computer (YouTube, any games you have or sound editing software, etc.). If you don't see stereo mix then right click anywere in the box and hit "show disabled devices" to see it.
To disable the linein just hit stop or start playing a song or video in Winamp.
Edit: Also, the beat detection seems to react to linein differently then stuff played on Winamp so you may want to retune the settings. That's a pain to do if you switch between both linein and Winamp but hey, free disco party is a free disco party.