You could try Sputnix's Autofiling feature.
I've been using it for some time, it's not 100% accruate but I would say it's fairly accurate in catagorizing your songs within a specified folder into sub-folders according to the singer/band's name.
The rest can be done manually, not much of a problem.
Only problem is, it's still in Beta, and you kinda need to register the program to keep using this feature. Good thing is although the registration fee is 12 bucks, you're kinda "allowed" to donate whatever amount you can.
*edit:correction, un-registered version auto-catagorizes the first 10 files in your specified folder*