Check your starter also, the starter is close to the PS pump so you could be mistaking it... you starter may be stuck and while your car is running its forcing the starter to go that fast, which would make it whine....

Also, theres a plate that goes through the front of your timing belt case, its pretty much a mount, check and see if it has loosend, cause if so it is twisting around and hitting your cam gear causing a high pitch wine... most the time tho, if you hit a bump it it will make the noise....

this happend to me, took me forever to figure out what was going on with it..

try also taking your belt off that powers your AC and PS, see if it stops the noise..