I will tell you what HandlerExploit told me AOSP.

Here is the problem with that explanation Czar

1)preference, im not sure what jaydubs preferences are but he seems to be liking CM. All i see is him wanting to add more of his personal touches and little tweaks (or big ones ;) )

2) AOSP is hard is hell. There is a reason that CM went farther that AOSP for us. There were some fixes probably already in the source itself or something, im not to sure as i wasnt part of the team while they started. If you talk to any Developer theyll tell you straight out that CyanogenMod makes building from source much much easier.

I would love to see a pure AOSP rom (I might make one) but i still have to get all the fixes that have to be implemented and so on.

thank you both for the quick response. i am interested in both aosp and cm. but am more looking for instuctions on how to customise my build. and info on porting as aosp pulled their porting section from the website.

Pure AOSP is difficult, but doable. To learn about compiling, I would suggest starting with the CM sources, and studying makefiles. Some of the most useful ones are the device files, where the configuration takes place, and the vendor files, where the customization takes place. You don't even need to download it, you can browse it from github.

I have already downloaded the gingerbread branch for CM and AOSP. I have built a CM rom already ( Thanks to the how to by ngiordano ) I will study the make files tonight thanks @phoenixsong6

also if I edit files in for example /packages/app/settings do these changes go through to the build and if so how do I edit these files and keep the original or do I just need to make copies?

Honestly I would say to look through all the commits for the cm source to see how the things work =)
Look at their gerrit and see all the changes that can sometimes be necassary to do a simple thing lol jk but seriously I think that would help the most with that ;)

all right I think I have completely confused my self . when I run "lunch generic_morrison-eng" What make files am I using?

@jassycliq I wasn't trying to sound sarcastic, but that is what HandlerExploit told me. Than silence ..... Thank you for a more detailed explanation.

lunch generic_morrison-eng calls Makefile (in the main folder) first, but that's just a pointer to build/core/main.mk

thank you i cant wait to get off work and play with it

http://forum.xda-developers.com/showthread.php?t=911142

nice little link for playing with aosp ;)