You probably have a worn front bearing/Wheel speed sensor.
In both case you need a new bearing hub assembly.

The bearing come with the wss (wheel speed sensor)
Intense-racing sold them now. 149$

a lot cheaper than the dealer.

It certainly sounds like a hub bearing. As Mark stated, swap your tires front to rear and see if the sound follows the tires.

Ok we rotated the tires from rear to front, and it still hums - so bearing it is. I took it to the tire store where I bought the tires and it turns out the manager has a 2000 Bonneville, but not supercharged.

We test drove before and after and we both hear the same noise. He said it'* not loose yet, and not in need of instant repair, if I don't have the money.

Since I am out of a job right now, every penny counts. The only symptom of a problem is the humming, nothing is loose.

Do you guys agree that it can wait a couple months?

Time on this type of thing is not possible to estimate.

They will hum and things for a while and then it will go bad and when it does, you'll need to fix it asap.

I drove on a bad bearing for 6 months. Just an FYI

@Rogue - how bad was it? Was it loose and shaky or just noisey

Noisy, sounded like a cupped spot in the tire.

You never know for sure, but I driven on a bad bearing for a while without a problem.
I'd leave it for now. But, bottom line... you're the one who'* taking all the risk.

How hard is it to break the bolts loose when changing the hubs? My SSEi has 65,000 miles on it and I will be changing them this spring. My son works at Advanced Auto Parts and can get them for about $80.00 apiece.

I usually don't have a problem with the mounting bolts. If you have any trouble, it will be will finding the right socket and removing the caliper bolts and the center bearing nut. Finally, sometimes the axle spline will be stuck in the bearing... but that is more common on Fords. Take pictures for the rest of us!