Disclosure: I know the guys behind it.
Try Cocoon (getcocoon.com). It's a Firefox plugin that is exactly what you're looking for - an alternative to Tor. Win, Mac, Linux (ahem most of the time anyway).
It does more than protect you browsing; for example, I registered for this/. account using Cocoon. The evil overlords at Geeknet don't have my real email address/identity.
Slashdot Mirror
Disclosure: I know the guys behind it. Try Cocoon (getcocoon.com). It's a Firefox plugin that is exactly what you're looking for - an alternative to Tor. Win, Mac, Linux (ahem most of the time anyway). It does more than protect you browsing; for example, I registered for this /. account using Cocoon. The evil overlords at Geeknet don't have my real email address/identity.