renamed eth0 to eth1, why?

[Neal Becker]

Mar  9 06:19:55 nbecker1 kernel: eth0: RTL8168b/8111b at 0xffffc2000034c000, 
00:23:8b:53:f0:80, XID 38000000 IRQ 17
Mar  9 06:19:55 nbecker1 kernel: udev: renamed network interface eth0 to 
eth1

Uh, why?  This notebook only has one wired interface.

2.6.27.19-170.2.35.fc10.x86_64