So I just ran into this strangeness in another fashion. On my MAC I cannot browse to the google hosted jquery, but in parallels on the same machine I can browse to it in Windows, over the same network/dns/etc connection.
But on the mac in both chrome and safari it will not browse to it.
Hrm. My chrome (on OSX 10.6.6) was able to hit the google hosted jQuery (opened it as text). My Parallels is working fine as well. I had a similar problem to the OP with Chrome earlier this week, but it was the Firebug Lite Extension breaking jQuery scripting.
Any chance you're running any extensions or browser tools that might be affecting both webkit browsers?
Have you tried FF on your OSX install?