my friend has a 90 integra gs its an auto. he wants to swap it to a 5 spd. what parts does he need other than tranny, clutch, shift linkage, clutch pedal, shifter. will he need to get a different ecu. and what other wiring is involved

 

Some you've already listed, but he'll need the following:

Tranny
Clutch Kit (with pp/tb)
Flywheel
Shift linkage
Shifter
Shiftknob
Clutch cable
Clutch pedal assembly
Tranny fluid
Brake fluid (for clutch)

He can use his automatic ECU, but the box located in front of the shifter will need to remain hooked up otherwise the ECU won't allow the car to start. And this method will also bypass the clutch on startup, so be aware of that before you try to start it in gear on accident.