It seems like a decent portion of people are having to change the dns/socks setting in firefox to get it to work. Seems like the type of thing that would be useful for Graham to include on the official instruction page at
Tetherbot
Anyway -- if you are reading this, and everything seems set up right, but you still cant load pages -- see this post to make sure your dns/socks setting is correct in firefox.
Browse the web from a tethered phone