I have a 1990 supra non-turbo. i picked it up pritty cheap but it runs great. It has an auto tranny that i want to change to a manual. i just want to know what would be involved in doing this.

Did you even try to find the info? :p
Like it's been said in every other auto/manual swap thread, assuming you want to stay n/a then you'll need a...
- n/a manual driveshaft
- W-58
- clutch and n/a pressure plate
- flywheel
- clutch pedal master cylinder
- slave cylinder
- W-58 transmission brace
- pedal assembly (clutch and brake)
- clutch hardlines
- and just a wee bit of wiring to get the backup lights and neutral safety start to work right again.
http://www.automotiveforums.com/vbulletin/showthread.php?t=200663
http://www.automotiveforums.com/vbulletin/showthread.php?t=174266
http://www.automotiveforums.com/vbulletin/showthread.php?t=172178
http://www.automotiveforums.com/vbulletin/showthread.php?t=160152

Thanks a lot you have really helped me out.

What does it involve? a shit load of money and even more frustration?

probably more than the car is worth. Just sell it for more than you paid and say to yourself, i just made some money. Then pick up a turbo mkiii.
then youll have a manual slow and ugly car =)

in all seriousness though, it will cost a whole lot of money. Way too much to justify the time and effort.

Not really, depending on where you get your parts and how much work you do yourself it could cost as low as $600 with a new clutch for the n/a.