Just a simple example which renders the light with the 'additive' effect. The result is that the shadows cut out areas of the light, and all lights on the layer add together, allowing multiple lights to work easily.
Heres two cap files.
The one that uses PS0.0 effects can be downloaded here:
http://www.fileshack.us/get_file.php?id ... ng+PS0.cap
And a smooth shadows one which uses PS2.0 can be downloaded here:
http://www.fileshack.us/get_file.php?id ... ng+PS2.cap
Oh and I used physics for movement on everything so you can bump the lights around. Enjoy!