Agribacterium methods or geneguns (biolistics?)

[hurly]

Would anybody know of any good articles/websites explaining the basic principles of these genemodification techniques? I've tried to google for some good illustrations but without any good luck.
The articles I found were not good either.

Can somebody help me out for my project?
I can actually write about any of the methods, but these two are most used methods? Or, what do you guys recommend? I think agribacterium is more difficult...