pseries (it is already changed to system p):
http://en.wikipedia.org/wiki/System_p
http://www-03.ibm.com/systems/p/
I'm too a beginning AIX-sysadmin/consultant
This is what i did:
read a lot of redbooks: This is my list:
- started with: AIX 5L and Windows 2000 - side by side.pdf
- then: p5 and pSeries Administration and Support for AIX 5L Version 5.3.pdf
- pSeries AIX System Administration.pdf
- AIX 5L v5.3 Installation and migration.pdf
- AIX 5L Installation and System Recovery.pdf
and so on
You should also get yourself a (little) IBM testmachine...
Good luck!