Shaddows - 4:05 pm on Jan 10, 2011 (gmt 0)
A quick search throws up:
And following that to source: (GOOG 10-K filed Feb 13, 2009)
Para 3 on that specific except page:
The first version of the PageRank technology was created while Larry and Sergey attended Stanford University, which owns a patent to PageRank. The PageRank patent expires in 2017. We hold a perpetual license to this patent. In October 2003, we extended our exclusivity period to this patent through 2011, at which point our license will become non-exclusive.