Open the Colorsync Utility. Navigate to the profile in question, and click the button labelled 'open' next to it.
In the list of fields, find the 'desc' tag. Edit this to whatever suits you and save the profile. This will change the internal name of the profile. You can also change the filename in the Finder if you want to...it's not a bad idea to keep the internal and external names in sync.
Note - just changing the file name is not enough. The internal tag is the description used by Photoshop etc, so this must be manually changed.