If you have already familar with NBU on RHEL(or other UNIXs and Windows), what you have to learn about NBU is not so much.
Reading docs(especially Device Configuration Guide) is enough.

Most of your requirements seems like matter of AIX.  I read some books about AIX, but those are written in Japanese, and might not suit for you.

That is probably the most important question here.

If not, then I've been able to learn a lot of Solaris just by reading the certification preparedness books, but of course they do not get into NBU specifics when it comes to daily task automation, scripting, etc.  You will need to learn the basics and then apply them to your NBU tasks.

If you have a training budget, then I would suggest checking out some learning courses from IBM. 

I found a small local training company that had class' on unix scripting.

I took a class to learn the basic unix setup, then the class to learn scripting.

If you go to the IBM training site you will see they also have shell programing class $3525!

As for awk ( and shell programing) go for the O'Reily books

unix in a nutshell

sed & awk

learning the Korn Shell

Learning the vi Editor

The Unix CD Bookshelf (3 books in one with a cd you can search)

I think the best books are the Safari books ( the ones with animals on them)

the best shell scripting book out there is

Unix Shell Programming by Stephen G. Kochan and Patrick Wood, by Sams publishing, ISBN 0-672-32490-3

It is not AIX specific, but goes over how to script in a very readible and learnable format.

Thanks for all the suggestions

I'll try and get an instructor led course for a AIX sys admin quick start, then try with books for the scripting side

It turns out that a collegue, who is a dark horse, has written this book

http://www.amazon.co.uk/LINUX-Shell-Programming-David-Tansley/dp/0201674726/ref=sr_1_1?ie=UTF8&s=books&qid=1258462284&sr=1-1

So I may give it a try unless its too dated now