Stellar Forces is a free turn-based multi-player squad strategy game.
Take control of an elite squad and defeat opponents in one of 50+ missions. Choose what to equip them with, where to deploy them, and then use whatever strategy and tactics you want to ensure victory.
This game is completely free to play - once you have registered you can play as many games as you want. You just need to download the client.
This game is played in a casual way, like a PBEM. Once you have taken your turn, your opponent is notified by e-mail that it is now their turn. However, they may not take it straight away. Typically, expect to take a turn and then wait about a day to take your next turn. Of course, you can play as many concurrent games as you can handle if you get bored in the meantime.