Last year, the Air Force acquired at least 300 PS3s for test purposes of the Cell Broadband Engine. The systems, now numbering at 336 PS3 units, are at Air Force Research Laboratory’s information directorate in Rome, N.Y.Now the Air Force wishes to at another 2,200 consoles to the mix, which presumably means that the initial test batch yielded pleasing results.
After inspecting the document on the Federal Business Opportunities site, it appears that the Air Force is not interested in the new, cheaper slim model. Rather, it is after the 160 GB model (CECHP01 or 989038) that was available in limited quantities before the 120 GB slim model arrived.

 The Air Force has used the PS3 cluster to stitch multiple radar images into higher resolution composite images, video processing, and building computers with brain-like properties.

Source

Brain-like properties? Can anyone say..SkyNet?