Get a letter from your Chief Pilot or Scheduling Dept. on Company Letterhead stating you are a Reserve Crewmember and can be called to fly international at any time. Go to the Federal Building @ Federal Building 11000 Wilshire Blvd., Suite 1000 Los Angeles (405 & Wilshire) first thing in the morning (call for hours). Bring about $140 Cash and the filled out form and photos(you can fill it out on their website). They will take all your info then tell you to come back at 2pm for your passport. It takes all day but you will get it.
Just a note leave your cell phone in your car, if it has a camera. They will NOT let you past security with a camera phone and you will end up standing in line again. I saw them turn away lots o' people who could not read the signs!