Most of the stuff you should get if you purchase the manual gearbox. Just double check to see what parts come with your purchase and get the missing ones.
Most importantly you'll need these items.
http://www.realoem.com/bmw/partgrp.do?model=CD12&mospid=47447&hg=25&fg=05 (Gearshift linkages)
http://www.realoem.com/bmw/partgrp.do?model=CD12&mospid=47447&hg=25&fg=10
http://www.realoem.com/bmw/partgrp.do?model=CD12&mospid=47447&hg=35&fg=05 (Clutch pedal and brake pedal. Manual brake pedal is smaller compared to auto)
http://www.realoem.com/bmw/partgrp.do?model=CD12&mospid=47447&hg=21&fg=10 (Clutch pump etc.)
You'll also need the driveshaft, because the manual gearbox is shorter (or was it longer, I forgot
). Also the clutch, flywheel and rear diff as well.
Might have missed something out so other sifus please help correct ya.
If you're interested I can get you in touch with someone who will be doing a manual conversion soon at a reputable shop. The gearbox he is getting is the original manual ZF gearbox for 328i. I think there's a few sets available soon sometime this month.