There are quite a few pool games (also called Pocket billiards) available for the iPhone on the App Store. But Sauce Digital claims that their iPhone game - Killer Pool provides "the most realistic pool experience" on the iPhone.

After playing it for the last few days, I must admit that its true. Killer Pool by Sauce Digital is just made for the iPhone (like Frenzic).

Killer Pool is developed by SD Games, the games development wing of Sauce Digital.

The iPhone game offers 5 different types of pool games such as the 8 balls, the 9 balls, the UK Black Ball (8 balls), Killer which is the classic multi-player game for up to 10 players and OctoKiller which is a customized version of Killer played on an octagonal table, where players eliminate each other by sinking their balls, with the last remaining player victorious.

You can play a single player or 2 player game. If you select single player, you have options to play a single match, a local competition or a world championship. If you select 2 player game then you can choose the number of racks you want to play with your friend.

The user interface is quite intuitive and easy to use thanks to iPhone's multi-touch capabilities. You can set the direction in which you want to play a shot by moving the virtual cue with your fingers to the left or to the right across iPhone's touch screen. You can also change the view of the pool table with your fingers by moving them up or down. You can then use finger swipe or the power meter to hit the shot with the virtual cue. I was more comfortable with the second option.

The movement of the balls on hitting the shot along with the in-play sound of the game adds to the realistic experience of the game.

You also have options to hit spin shots or swerve (I haven't tried them out). The graphics are quite good but they can get a lot sharper. The other good thing is that you can play the game in portrait as well as landscape mode.
 
Unfortunately, after playing the game for the last few days I have realized that I am as bad playing the iPhone game as I am playing the actual pool game. 

Jokes apart, Killer Pool is not only one of the best pool games available on the App Store, it is also one of the best iPhone games that I have played. If you enjoy playing pool and looking for an iPhone game then I would recommend you checkout Killer Pool.

I don't want to sound demanding here but one feature that would have made this game perfect is the online multi-player capability that is offered by free iPhone game Adrenaline Pool Lite (iTunes link).