Well this is an old trick but many people i talked to didnt even knew about it....so i am putting up a little guide for it...its a small process and takes 2 mins.. 
1. In ur winamp start visualizations..
2 in the visualization window that opens right click on it and click on AVS editor
3. in thw AVS editor window go to settings and click on Display settings
4 In the display settings check the boxes for Overlay mode and set desktop to color.
5 start a song and minimize winamp....Enjoy.. :hap2: and if u have a projector project ur desktop on to a wall and u will have instant disco visualizations :clap:
Note. This process uses up huge resources.
1. In ur winamp start visualizations..
2 in the visualization window that opens right click on it and click on AVS editor
3. in thw AVS editor window go to settings and click on Display settings
4 In the display settings check the boxes for Overlay mode and set desktop to color.
5 start a song and minimize winamp....Enjoy.. :hap2: and if u have a projector project ur desktop on to a wall and u will have instant disco visualizations :clap:
Note. This process uses up huge resources.