When I applied back in October, NAS was posting ads occasionally on Climbto350.com. However, the ad was only up for a day or two and then it was gone. Previously, I tried the online applicant system at
www.nasaviation.com. However, I never received a response from that. Within a week of submitting my resume via the Climbto350.com ad, I was called for an interview.
NAS contact info (address, phone, fax, and e-mail) can be found on their website.
Good luck!
Cheers,
C17
P.S. I heard they are interviewing in Dallas at the end of this month.