Where is a good site that i can learn some information about the various weapons...

[Anti-Christ(ian)]

...in halo 3? Right now i am only comfortable using the marine weapons (like the battle rifle and rocket launcher). I would like to read up on which weapons are better in certain situations.
Any information on weapons would be great, or if you know a great site that would be even better!
Don't everyone answer at once now! Wow, i can't believe more people don't answer these questions.