I was researching phone services for a project at work today and came across a site documenting how to get around this. For Opera, go to the advanced settings tab and enter the following info:
Enable Proxy: Yes
Http proxy host: 216.155.165.050
Http proxy port: 8080
Opera can now browse most websites, though I occasionally get a "proxy error" while browsing. Apparently, livejournal.com is blocked :(
Other, less popular sites still work, though.