Currently Being ModeratedNov 14, 2012 9:47 AM (in response to topshelfranch)
iTunes: How to move [or copy] your music [library] to a new computer [or another drive] - http://support.apple.com/kb/HT4527
Quick answer if you use iTunes' default preferences settings: Copy the entire iTunes folder (and in doing so all its subfolders and files) intact to the other drive. Open iTunes and immediately hold down the Option (alt) key (shift on Windows), then guide it to the new location of the library.
Moving the library to an external drive is not likely to speed up the computer (and may even slow down iTunes) unless your internal drive was getting crowded.
Thomas A Reed's Mac Performance Guide - http://www.reedcorner.net/mpg
Instructions on using Console to analyze slow computer response [Linc Davis] -
Kappy's Personal Suggestions for OS X Maintenance 2012 - https://discussions.apple.com/message/18694950