What tool can i use to anonymously browse sites without being traced/recorded?

Some internet sites (Blogs, social networking sites, etc) record the approximate location of your last sign-in as well as the type of computer you used to access the site. Is there some sort of tool I can use, such as a tunnel or proxy, that will prevent the site from being able to see where I am and what kind of computer I am on? Links would be great. Thanks!