As Michael Phelps, Elizabeth Beisel and Dana Vollmer competed earlier in today's Olympic Swimming Heats, they will prepare to participate in the Semi-Finals tonight, in Day 3 of the trials in Omaha.

Four Finals will take the spotlight tonight. 

The Men's 200M Freestyle is led by Phelps and new official rival, Ryan Lochte. The two winners of this trial will join the U.S. team in London, but chances are that Phelps and Lochte will swim to victory later this evening.

The Women's 100M Backstroke will feature 17-year old, Missy Franklin, who had the best qualifying time in the Semis, completing the trial in 59.06. This was just .04 seconds faster than Rachel Bootsma who finished in 59.10.

Matt Grevers took the fastest time in the Semis and will look to gain entry in the Olympics as he gets ready to compete in the Men's 100M Backstroke.

David Plummer and Ryan Murphy finished close behind Grevers in second and third place respectively.

The last Finals that will be decided tonight will be the Women's 100M Breaststroke. Rebecca Soni and Jessica Hardy will try to finish in first and second, like they did in Tuesday's Semis.

The three Semis tonight will be the Women's 200M Freestyle and 200M Medley. The men will battle to qualify for the 200M Butterfly.

The trials could be seen on NBC tonight at 8pm EDT.