You may want to lightly lube the shifter, but don't disassemble it unless you want a pile of cogs, springs and ratchets that won't go back together. There should be a way to take the cover off though to put some lube in. As long as it works though don't do too much.

Look at this post http://www.bikeforums.net/showthread...imano-Brifters for some info on cleaning without disassembling, if you haven't already seen it.