A friendly riding-in-the-rain video from the San Fransisco Bicycle Coalition:
I suppose being a fair weather biker is better than not being a biker at all, but come on. It’s just a little water. Riding in the rain is fun. If you have fenders and a rain jacket of some kind, you really won’t get all that wet.
As for riding tips, just go slower and avoid metal grates, especially with road tires. Third Ave downtown becomes slightly more treacherous (because of the transit tunnel vents) and riding on the grates on bridges may result in broken bones (just ask my friend Kelli).
Simply take your time, brake gradually and enjoy the sounds of the rain. Biking to work when it’s a nice day is great. But biking to work when it’s rainy makes you feel like a huge bad ass. And biking in the rain can help you get over a dreary day, while driving only makes you more depressed.