According to Variety and Comingsoon.net:
Sanaa Lathan (Out of Time) will star as the lead in 20th Century Fox's Alien vs. Predator. Shooting begins October 28 in Prague, and Fox will release the film in August. Paul W.S. Anderson is directing from a script he wrote with Shane Salerno.
Lathan will play explorer-adventuress Lex Kline, who leads an expedition to Antarctica to uncover warring alien races. The Kline character is said to be reminiscent of the Ellen Ripley role Sigourney Weaver played in the "Alien" series.
Lathan stars in the film alongside Italian actor Raoul Bova (Under the Tuscan Sun), who plays an archaeologist, and Lance Henriksen, as the industrialist who finances the expedition. British actor Ewen Bremner also stars.