For links, lucidity.com is probably the best, though I imagine there are other sources on the web besides, just do an engine search under dream lucidity or lucid dreaming.

It is essentially the process of learning dream control, and through intent and awareness to become their guide. Once the lucid dream plain is achieved, it can be one hell of a ride.

Remember the song Silent Lucidity, by the band Queensryche? It is about lucid dreaming, go find a copy and give it a listen, that'll provide one perspective of the whole thing. Or if you're feeling lazy just traipse over to www.themomi.org, I think they used to have a MP3 file of it somewhere.