99 Grand AM "popping noise from spring"

could be your strut mounts are worn out or broken. My car did the same thing, and it turned out that I had a broken spring. I replaced it with a pre-assembled strut and shock, which included the mount, and that did the trick.

my 2001 grand am gt makes that noise when the brakes are applied

My wifes 1993 Pontiac Grand Am had similar symptoms. There was a popping sound coming from the front suspension area. It didn't always happen but when it did, it was during braking, a turn, or going over a bump. After inspecting the suspension, realized that the stabilizer link bolts were broken, and the popping noise was the broken pieces of the bolt (part still attached to the stabilizer, part still attached to the lower control arm) being forced onto eachother hard enough until they slipped, and the upper piece would then smash into the lower control arm. Replaced link bolts (~$20.00) and not only fixed the problem, but the car handles sooo much better now. The broken bolts weren't as easy to see as you might think, depending on the position of them. If the two broken pieces were pushed together they still looked whole at first glance (although extremely corroded/rusted). Upon closer inspection, however, it was easy to see the separation. Putting the vehicle on a jack made it even easier to spot, as this drops the lower control arms and pulls the two pieces of the bolts apart.