As far as the body modeling is concerned, all of the relevant information can be found in Chapter 2 of the book "Maya Character Creation" by Chris Maraffi, and the facial modeling and rigging can be found in the book "Stop Staring" by Jason Osipa. Definitely check those books out, they describe the process more adequately than I could with a tutorial.
Also, check this tutorial out, it covers polygonal modeling and texturing:
http://www.3dm3.com/tutorials/maya/highmodel/