What is the best free software out there to hide the IP while surfing the net?

I think for some reason the ISP I'm using has been prohibited by one of my favorite websites. I need a free software that could hide my IP at all times while browsing the Internet. I have tried to proxy servers on the network but they are useless when you want to register your username and password or when you want to download something. I have tried to delete cookies and temporary files, etc, but that does not solve the problem. Is there any software out there that a good deed? preferably free?

This website and it http://www.recipehotel.com/cgi-bin/index.cgi: http://proxify.com/ block your IP and allow you to get around the firewall so you can get on websites that are blocked. They are easy to use and not have to download anything. Simply plug in the website you want and then you're there.

Linux HOWTO #3, Part 1: Anonymous Web Browsing with Tor

Anonymous Surfing $11.80 The FTC estimated that close to 10 million people in the US were victims of identity theft last year. Protect your personal information, credit card numbers and financial transactions from online snoops with Anonymizer 2005. This powerful privacy protection program uses 128-bit SSL technology to create an encrypted path between your computer and the Internet to shield you from even the most sophis…