True Combat Elite happens to be a total-conversion modification of Wolfenstein: Enemy Territory by Team Terminator and Groove Six Studios.
The game is free and playable across all platforms.
Notable features include iron sights aiming (no crosshair), multi layer object penetration, letterbox / wide screen view modes, lag compensation, client side bullet prediction and support for PunkBuster, the anti cheat software.
More from the game site here... http://www.truecombatelite.net/
Source: Free Online Fun