There is a good thread from a little while ago discussing the pro's and con's of disconnecting the ISC. It is worth a read for anyone seriously interested in tinkering with it.

Another solution is to replace the gasket in the ISC with a peice of solid cardboard (ie. cereal box) cut to size. This renders the ISC useless, but without the logging of error codes that occurs if you simply unplug it.

Most people will also find you may need to adjust your base idle slightly if you decide to do without the ISC.