Hide IP Platinum is great. I've used it for stuff like getting a @hotmail.com email address instead of a @hotmail.co.uk address etc. You can grab it here: http://www.soft32.com/download_102515.html Its a trial only.
It all depends on what you need an IP masker for, and the amount of security/privacy you need.
Do you mean record companies, film studios, and the FBI? lol
you could use PeerGuardian. Its a small program that blocks connections from known IP's of record companies etc., so that they cant see what you're sharing/downloading when using P2P (filesharing) software. grab it here: http://phoenixlabs.org/