Doesn't hold up for squat in court.
Go to the US Copyright office's website
http://www.copyright.gov/ and download the forms you need for what ever type of work you are submitting. Create a lead sheet with at least the basic chord changes, and a melody line, and lyrics, (If any) and a copy of the work. Write a check for 30 bux for each work and send it off to:
Library of Congress
Copyright Office
101 Independence Avenue, S.E.
Washington, D.C. 20559-6000
Depending on various things, you may get your copyright cert. back in 8-12 weeks, for me, it took aver 13 mos, last song I copyrighted, due to the anthrax scare and the implementation of sniffing equipment. Everything was put on hold until they could verify that things were clean.
Anyway, IMO the more thourough you are about depicting and describing the work to be copyrighted, the better your chances are in court if it should ever arise.
Hope this helps.
One other trick if the 30 bus per work is a tad much, you can put a number of songs together and name it a 'suite' and copyright the 'suite' saves $ on a large number of songs and you're still protected.
Good luck,
Bamm