[iTunes] library consolidation

[bert.bates]

I'm sure this has been discussed a million times - I apologize  
upfront. So, maybe there is a written resource you can recommend.  
Somehow my iTunes data has become spread across directories on two  
different hard drives. I want to do two things:

1 - get everything back under a single directory.
2 - move everything to a new, improved hard drive.

Thanks!