I ride in the rain, but after my incident last Friday (http://www.bikeforums.net/showthread...took-14-months), I may take the car in heavy rain.

Important things are fenders to keep the grimy road water off of you, and decent waterproof clothing. I don't do any special post-ride cleanup. If it rains a lot of days in a row, I may relube the chain, but only if it needs it.