I imagine any of the chains that do suspension work will install them for you. When I had my 00 Runner I let Toyota install Billsteins for me, they charged me 2 hours for the front and 1 hour for the back, so 3 total, not that you are going to the dealer, but a reference point anyway. The work isn't all that hard, the rear is probably harder than the front as the top bolt is a pain in the ass and prying the new springs takes a bit of muscle. The front is pretty easy if a spring compressor is available.
On a side note I just did the same setup on my 02 on MLK Jr. day, I love the new ride and I'm sure you will be pleased as well.
Another note, if you have a Sport tell the shop that your rear shocks are completely filled with oil, shaft and all. My friend and I torched off the left side, which erupted in a huge fireball, which was cool. He was a Toyota tech for years and said that had never happened before, so we assume the Sport has different shocks.