How to assign blackberry led indicators ?

Hi friends,
Today I purchased a Blackberry curve mobile phone. I am really impressed by its features and very happy to have this phone.
I explore all its features; it is user friendly and easy to use.
The only thing that I did not understand is the LED indicating features.
Can I assign different LED colors to different contacts?
Can anyone tell me about Blackberry led indicators and how to use them?
I am waiting for a rapid reply from a Blackberry lover.
Thanks
