I use Park Tool's Cyclone Chain Scrubber. I fill the reservoir with the same citrus degreaser that I use to clean the rest of my bike. I also use Park Tool's GearClean Brush to really scrub the chain, the cassette, the chainrings, and everything else the chain touches.

When I'm done washing and rinsing the bike, I use a clean rag to dry it as best as I can. Then I bounce the bike on the rear wheel to try and shake out as much water as possible, and use the rag some more. Then I let it dry overnight.

The next day, I lube the chain with the appropriate Rock N Roll chain lube. I use Extreme on my MTB, Absolute Dry on my road bike, and more recently, Gold, which I use on both. Rock N Roll lubricates and cleans the chain, so I use that between washes. I've become a huge fan of the stuff. It's kinda hard to get here so my friends and I buy it by the case.

Regarding WD-40: I'm no expert on petroleum products, but pretty much everyone has told me to keep the stuff away from my bike.

Oh, and for handwashing, I use lavender-scented Johnson's Baby Oil. It works like a charm, it's cheap, and it smells great.

~Cari