okay, a simple task but a bit of an enigma. here it is explained, pictures from my (very dirty) 2001 ZX3, but the process was the same with my wife's 2001 SE as well.
1. open the trunk or hatch, get it up to eye/hand level. it's a lot easier.
2. remove your license plate (otherwise it gets wedged in once you free it from it's socket)
3. pry gently at the right (passenger) side of the light lens. i used an old keychain, but anything wide and flat should do well. (pictures 1 & 2 & 3)
4. the light will shift to the left as you pry, then it will move downward with the pry lever and pop out of it's hole. (picture 4)
5. the light is out, (picture 5) now remove the bulb from it's copper contacts and (gently) snap in the new bulb. i gave the bulb a bit of a twist in the holder, just to remove any oxidation on the contacts.
6. gently snap it back into it's hole, inserting the left side first.
7. test it out - turn on your parking lights (the license plate lights should come on even if you don't have the engine running or keys in the ignition)
8. replace your license plate and close your trunk before you drive away
that's it. note: the lights are not symmetrical; the spring is still on the left side for the passenger-side light (picture 6). this was a bit of a surprise.