I just bought a 2005 K2 Attack 2.0 and when I went to register it the site asked for a BIN number. Where do I find the BIN number? (It isn't anywhere in the manual)

You might wnat to email them and asked. I never registered mine i just keep my receipt But they usually reply within 24hours.

The BIN is stamped into the bike on the bottom of the bottom bracket.

I thought that was the serial number. You learn something new every day

The BIN for my trek is on the bottem bracket. Might not be true for other bikes.