Caleb Porter has added three players to the U-23 camp roster (Matt Lampson, Brian Perk and Royal-Dominique Fennel), while two players (David Bingham and Gale Agbossoumonde) have withdrawn from the camp due to injuries.
The U-23 camp has started up in Carson today and it looks like they will play two scrimmages against the USMNT before heading to Costa Rica next Wednesday for games there against Alajuela and the reserves of Deportivo Saprissa.
Also, I have heard some rumblings that the USMNT will play one of its first qualifiers in the LA area (likely Home Depot Center). My guess would be the game against Antigua and Barbuda in June, but that is just a rumor at this point.
And one non-USMNT link, but Brian Sciaretta has an interview up with Villyan Bijev over at the NY Times Soccer Blog.