Auto to manual:
You will need (if you want a factory appearance),
Steering column and ignition switch for a manual
Pedal assembly, including master cylinder and clutch pedal
Clutch line and slave cylinder
shifter assembly and interior shifter surround plate
Shift cables for the transmission you choose
manual transmission ECM, and manual transmission & engine wire harness (or adapt yours)
interior harness for clutch safety switch, cruise control cut out, etc (or adapt yours as needed)
radiator
a GM Metric bellhousing bolt patern, Getrag 282MT2, or F23, Muncie MG2, or MG1 plus mount brackets for the transmission (rubber mounts are the same for auto or man)
flywheel, clutch & clutch cover, and through-out bearing for the engine and transmission combination you're using
Axles
The amount of work is up to you, much of that could be left undone, or worked around.
Have you considered getting a 4T60 (or 440-T4) 4 speed auto for a swap?
The rest of the car is setup for it already, and that would give you better gas mileage and performance for less money.
-Dave
[This message has been edited by IFLYR22 (edited 06-24-2012).]