What rukee said. Support the car on stands (good ones!), get a good solid bite with a floor jack under the A-arm, remove the top or bottom spindle nut. Once the nut is removed you'll need to whack the spindle good and hard with a heavy hammer to pop the tapered ball joint out. Slowly lower the floor jack until you have the room to separate the spindle from the arms. If it's easy enough you could remove both nuts from both joints before lowering. I also know that F body front springs can be swapped w/out a compressor. A crow bar or a long pry bar will pop em over the pocket on the lower arm and you can simply jack it up into place with a floor jack. Of course if you'd feel safer using one then by all means, go for it. If you work alone a spring compressor isn't a hateful idea either. If you're doing one side at a time, no need to undo the spring as well. Good luck and enjoy your new brakes, and for that matter the swap job too.