Besides the three Shockwave Flash teasers at nin.com, two other clips of NIN material previously unreleased have surfaced on the internet. One, a 43 second clip with slow pounding drums and buzzy guitars, is a clip of the Nine Inch Nails cover song started back in '95, Metal, written first by Gary Numan. If you haven't found it yet, you shouldn't be reading this. Origins point to the bulliten board now linked to by nin.com, but the clip was released by a fellow posting to alt.music.nin.
Also released, a clip of the first two teasers from NIN.com with about 20 seconds of extended material not found elsewhere. This was leaked by one Ironpig, who's IP pointed back to TRENTGATEWAY@nothingstudios.com.
Apparently there are a total of four leaked clips on the net. It is assumed that Metal is one of them. The other three haven't showed up, and could even just be a hoax.