I use simple green diluted about 1/3 Sg and 2/3 water. I put this in a small ultrasonic cleaner for about 10 min and then rinse w/water and then maybe Isopropyol alcohol. The chain is sqeeky clean. I do a lube, usally the dumonde stuff and wipe off excess and for dusty summer MTB I wipe the chain w/ rag in Iso alcohol. this gets the chain lube off the exterior of the chain where it only colllects dust.

Works great IMHO.

But... check this out about simple green
http://www.bikeforums.net/archive/index.php/t-4117.html

appearently if you leave in SG for a long time it corrodes the chain (or other parts). I have not had any problems but I don't leave in the SG very long and I do a water rinse to get the SG out. I also pitch my chains when the show
1/16" of stretch.

I like the SG as there is no solvent to get rid of. Mineral sprits are fun to burn though