2000 Pontiac Sunfire How do I replace the wheel bearings?

When I had an alignment done on my car recently, I asked the mechanic to check out a knocking noise coming from the left fron corner of my car. I can hear it any time my car is moving, whether I'm speeding up or slowing down, or driving the same pace. The mechanic said the wheel bearings are about to go out on the front driver side. How do I replace the wheel bearings? Does the axle have to be taken off? Do I need to get my car on a hoist, or will jacking up the front be enough? Thanks for your help.