Thats not exactly what I meant, Im aware of the effects methods...a harmonizer such as the Eventide 3000 is very nice...expensive, but nice. I was more interested in the recording techniques using multiple lead guitar layers. Agreed you can use effects, however the effects tend be 'robotic' in nature in that they basicly shadow EXACTLY whats put into them, whereas a manually replayed line that is say delayed will have subtle differences that add characteristic style to the line. I was wondering is anyone had interesting techniques that they would like to share.
I'll give another example
On the GnR track "Nighttrain" Izzy is playing rythem out of the Left channel...Slash is doing Rythem and Lead out of the right channel...but they mesh so well together that if you were to turn one of the channels off..it would be a totally different song (try it sometime)....anyone have techniques?