It's being held on the O'Reilly campus in Sebastopol, CA, USA
Previous Foo event coverage for 2003 here and the wiki for 2004 here
My mate Surj went last year and said it was a blast, very informal geek sleep over party !!
Foo Camp is a creation of the people who attend. We're inviting people
who're doing interesting works in fields such as web services, data
visualization and search, open source programming, computer security,
hardware hacking, GPS, and all manner of emerging technologies to
share their works-in-progress, show off the latest tech toys and
hardware hacks, and tackle challenging problems together. And in case
you're wondering, it's Foo because the Camp's for Friends Of O'Reilly
(and because I like bad puns)