I've been using squid for several weeks and found that it has problems in accessing pages at times for strange reasons. For example, sometimes I am forced to type google.com into the URL window instead of entering my search straight into the search window of the browser (which links to google). At other times it will work flawlessly--so it's been somewhat hit and miss, and I have been unable to find meaningful errors or reasons why.
I hope you can find a simple proxy, but I'm unaware of any. I would be happy to hear of it too when you find one.