I have to agree w/ W222. It takes some time to receive the offers, besides I don't believe the website where PIs browse to look for new pre-IRTAs has been updated lately. Be patient. But if you want, you can send a message to the clubPCR (gosh, sooooo nerdy) email list.
http://preirta.nih.gov/valuable.htm you can get lots of helps and advices from it.
Also, W222 is right. It's EXTREMELY IMPORTANT that you pick a good lab. not just in terms of research that you are interested in, but also a PI who is understanding and caring about your situation. Not only because he/she will train you to do good science (if you are MSTP-oriented or just love research), but he/she will be the one who writes perhaps the most crucial recommendation letter for you. If it's not for my boss's amazing letter, I don't think I'd be at where I'm now.
I don't know which type of pre-IRTA you are applying as (post-bacc, academy or technician?) but I highly recommend post-bacc, unless you don't mind repetitive jobs (heard someone has to do 500+ PCR everyday, and that's all he does). And even if you are applying as post-bacc, make sure that when you are picking a lab, pick one that won't treat you as a tech (ask about job description, are they going to give you an independent project, will they include your name on any publication, etc)
Good luck. I am leaving NIAID/NIH in two months, but these past two years here are the most fulfilling in my life. Hope you'll enjoy your stay at NIH too