strange noise

[68jimmy]

In the last couple of days i've noticed a squeak/squeal (?) when driving. At first I though it may be the ps pump as it occasionally makes some noise. So after opening the hood and listening while revving the motor, no noise. So I drive it again to see if I can narrow i down. It starts at about 15mph and continues until I come to a stop.
So I figure it may be the carrier bearing for the driveshaft. So I place the rear of the truck up on jackstands, start it and place it into drive. As I'm sitting in the cab and revving the engine a bit with the wheels spinning at about 30mph there is no noise... So now I'm thinking it maybe coming from the front-end. Would a front wheel bearing that is going south make a squealing noise?

Any help appreciated!