A:
bestbuy.com
services
scroll down to "car electronics professional installation"
scroll down to "standard speaker installation"
add to cart
You'll get an option to purchase "Total Tech Support". If you don't want it click on "Go to Cart".
checkout
From there you're on your own since I don't remember what happens and I no longer need to pay for an install. But I'm sure that you can schedule the install from there.
BTW, The install for my 2 speakers was only 30 minutes. Your mileage may vary. I was going to do it myself, but when I tried to remove the rear door panel the clips were very tight and I figured I'd rather get a professional install than buy 1 or 2 door panels. The tech did a great job.
Hope this helps.