Instead of a real http proxy (like Psiphon), the best implementation would simply let you append a URL to your Unite URL and get a website back, like "http://foo.bar.operaunite.com/www.cnn.com/". That would get rid of handing over your cookies to an unknown third-party; it'd probably also discourage people using the service for private communications (no https, in Unite -- it'd be great if Opera fixed that!).wanted: spartacus, an opera unite web proxy for iran (Thanks, Danny!)
Maybe I'd also stick in a geoip check to make sure the incoming requests are coming from a known Iranian IP block, just so users could feel worthy that they're just catering to Iranians (you could pull them out of this free geolocation database). That way we wouldn't be creating a permanent global clunky, insecure proxy network -- or at least not until Iran recovers and starts its own phishing services.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.