It's signed with Wladimir J. van der Laan's key.
This is the fingerprint I have:
pub 2048R/0x74810B012346C9A6 2011-08-24
Key fingerprint = 71A3 B167 3540 5025 D447 E8F2 7481 0B01 2346 C9A6
uid Wladimir J. van der Laan <
laanwj@visucore.com>
uid Wladimir J. van der Laan <
laanwj@gmail.com>
sub 2048R/0xF69705ED890DE427 2011-08-24
Though I haven't verified it.