- Remove the screw above the bag holder, just to the left of the glove
compartment.
- Open up the ashtray and cupholder trays - this is to prevent scratching
the fronts later on
- Remove the entire center bezel panel by pulling it off.  Start at the bag
holder - just give it a good yank - the panel is held in place with metal
spring clips (which will scratch up the fronts of the cupholder and ashtray
had you not opened them up first)
- Once the bezel is removed, rest it on the cupholder, and disconnect all of
the electrical connectors (they're all different, so no need to worry about
getting them mixed up)
- Set the center bezel aside
- Remove the four screws holding the radio in place.
- Slide the radio out, and disconnect the electrical and antenna connections
from the rear

Installation will be the reverse.  Be warned that the antenna connector
isn't a standard GM-style connector, so you may need an adapter to go to an
aftermarket unit.