Here is a mod I did on my 2002 Corolla (8-gen).
The 8th-gen Corollas did not have keyless entry systems (at least mine didn't). It did have electric door locks, but no Keyless Entry and no way to open the trunk with out a key, or pulling the inside lever.
Since it did have electric locks, I purchased a Hornet Keyless Entry system from Circuit City and had them install it for me. Cost with free installation, $75.
Hornet Security Keyless Entry System
Then, I bought an electric trunk release system from Slickcar.com. Cost: $20 plus shipping.
Power Trunk Release Kit (Universal)
Then I had to do a little fabrication work to make the (universal) trunk release solenoid mount inside the trunk.
I bought a piece of 2-inch by 1/8th-inch aluminum stock from Home Depot, and cut it to fit across the reinforcing ribs on the underside of the trunk. I made it slightly longer than necessary and arched it slightly for two reasons: It holds the solenoid tight against the trunk lid so it doesn't move (sort of like a leaf spring), and by arching it, it has less tendency to flex. The aluminum strip is held to the ribs with 4 heavy sheet metal screws (2 on each end). (Picture #1)
I had to permanently remove the black plastic cover piece that goes over the latch mechanism, but I was able to put the glow-in-the-dark emergency release lever back on. I also had to drill a very small hole in the lever that the regular release cable connects to, and through that hole, I connected the hook that comes with the solenoid kit. The cable from the solenoid connects to this hook with a set-screw. (Pictures #2 and #3)
Then it was just a matter of running the wire to the Hornet keyless entry system that I had previously purchased and had installed by the guys at Circuit City. You will also need to wire in a relay between the keyless entry box and the solenoid; the soleniod draws 15 amps (more that the Hornet box can handle.)
Total cost, not counting the Keyless Entry system, was under $30.