So wait… you have a 60gb hard drive and 20gb of music? Your boned…
60gb is more like 55-56 actual gb, and if 20 of that is music, you already down to 36gb. The OS is around 10 gb, im sure you have tons of random applications and .dmg files sitting in your applications folder that arent extracted and you wonder why they dont work. Maybe a few .exe’s, then 1gb of documents and random crap., so you really cant have much more than 10-15 gb free if you delete everything you dont know what it is. And then bootcamp is 1/2 a gb, and you need to have 5gb free on the os x partition for it to allow you to partition it, so the MOST you could have is about a 10gb partition, wich is more like 9gb on a base install of XP, aka… one game…
Basically, get a new HD if you want windows. 60gb is pathetic.