I am a beginner in creating things in GECK and would like to know where I can find a tutorial for creating armor and clothing; especially for the HD Berry body replacer?

I do not recommend you start with modelling armor or clothong immediately, try some smaller misc objects first, but if you must:
http://www.fallout3nexus.com/downloads/file.php?id=13644
I cannot renember if it includes everything you'll need, probably not texturing and blender basics, but it's the best i can do.
Also simply try googling if you dont get something. There are a lot of tutorials and help pages on modelling uploaded that i dont know of the top of my head.

I haven't touched on modeling but hopefully http://www.youtube.com/watch?v=aaLLOm8_bgA maybe of some assistance to you.

bigcrazewolf