Google (Googlebot)

From To

64.233.160.0 - 64.233.191.255
66.102.0.0 - 66.102.15.255
66.249.64.0 - 66.249.95.255
74.125.0.0 - 74.125.255.255
209.85.128.0 - 209.85.255.255
216.239.32.0 - 216.239.63.255

MSN/Live (MSNBot)

From To

64.4.0.0 - 64.4.63.255
65.52.0.0 - 65.55.255.255
207.46.0.0 - 207.46.255.255
207.68.128.0 - 207.68.207.255

Yahoo (Yahoo! Slurp)

From To WHOIS

66.196.64.0 - 66.196.127.255
66.228.160.0 - 66.228.191.255
67.195.0.0 - 67.195.255.255
68.142.192.0 - 68.142.255.255
72.30.0.0 - 72.30.255.255
74.6.0.0 - 74.6.255.255
202.160.176.0 - 202.160.191.255
209.191.64.0 - 209.191.127.255

I did not checked all of them, but the list seems correct, can be useful to some, thanks

tnx it is very useful