Cleaning the chain is easy if you do it regularly (say, every 250-300 miles depending on the conditions you are encountering). Get a cleaner (I use Pedro's Organic Degreaser) and a cleaning machine and, if you are feeling really fastidious, a chain holder for when you remove your rear wheel. Run the chain through the cleaner with the degreaser, apply some degreaser with a brush to your chainring and cogs, and check your tires etc. In about 10 minutes, gently hose down your chain and rear cogs and use a wet rag to wipe down your chainring. Wipe everything down with a clean cloth. Spray a good quality lube (I use a teflon dry lube from Finish Line). Replace your rear wheel. There; you're done!

Cleaning your chain and chainring and cogs won't take more than 15 minutes, so if you ride 500 miles a month, you are talking about 15 to 30 minutes per month on average. Or you can go over your entire bike with a fine eye then...that usually takes me about an hour, but I am pretty anal about keeping everything in good working order. I expect a lot out of my bikes....so I make sure they are ready to take it.

If you are keeping your bike clean like this, depending on the amount of gunk your bike picked up in the rain, you could just wipe her down and spray a little dry lube on the chain until the next cleaning. Oh, and make sure no water has entered into your BB via your seattube - I found this out the hard way: http://www.bikeforums.net/showthread.php?t=58502