Just get Tunnel Bear (VPN) and then use Pandora all you want... (or up to their free monthly bandwidth limit before needing a paid account)
Also, if you have a US address, you can signup for Spotify (using a VPN). I'm paying $9.99/month for the Premium plan and love it. Best music service I've ever tried by far. And, once you have the Spotify account and program installed you do not need the VPN anymore. It works great here.
in grooveshark, there's a radio button in the bottom right corner, which makes it work a lot like pandora. otherwise it works like spotify but without the ads.
the interface isn't the most navigable, however...
I had a spotify account in the US and loved it... however it doesn't work here anymore. it can tell my VPN is in Argentina. tips on how to make spotify work here? for now i just use grooveshark which isn't nearly as good as spotify (can share playlists with friends back home with spotify)
Grooveshark is nothing like Pandora...you can literally leave Pandora on for hours and hours and all the tunes are on the vibe you're after...I'll check TunnelBear, but Ultrasurf and Hotspot Shield both work OK.