99 Dodge Intrepid: Air sound can be heard and continue when slightly depressing brake pedal. Goes away when fully depressed. Brakes seem fine otherwise, no hard pedal etc. Vacumm leak? and where would the be typically?

The brake assist is bad. Its located on the firewall. The brake master cylinder bolts to it. The rod comes from it to the brake pedal

Under the hood on driver side, the big black round brake booster which is attached to the firewall, has a vacuum hose going to it, which is connected to a one check valve that just pushes into a rubber grommet on the booster. Have someone step on the brake while listening for air exscaping around it.
Most likely the diaphram inside the booster is leaking, and the only fix for that, is to replace it.

Yes sounds like a vacuum leak, it could be a cracked pipe that goes from you air intake to the brake booster which is located under the brake oil reservoir.