Click here.

888Poker. 888Poker, .ES, WSOP.co.uk & others.
Full Tilt.
GTECH G2 Network. PokerHeaven, VirginPoker & others.
iPoker Network. Titan Poker, Bet365, Everest & others.
Merge Network. Carbon, RPM, Hero & others.
MPN (MicroGaming) 24hPoker, Ladbrokes, NordicBet & others.
People's Poker Network.
PokerStars.
Yes, it is legal to use a VPN to play at PokerStars if online poker is allowed in your country. However, keep in mind that VPN usage doesn't make an illegal activity into a legal one. So, if you live in a region where gambling is extremely frowned upon, you might still get into trouble.