How to do a factory reset to a blackberry cellphone?

[koolaidman]

Ok so I want to have my bb as if it was just fresh out of the box and I've heard about the factory reset which wipes out everything that the phone has stored in it. So my question is if it really does that, like what does it erase, how do you get it to do that, and after that process what will happen, see I still have half a year to go with my carrier and want to keep using it without it being all messed up so will it have all of the information it had (my plan,pin, etc), will I be able to use it normally again or will I have to contact my carrier for them to send their info to my phone in order to have access to the internet and other features.

Thanks for your help, and I'm looking only for serious answers that know what happens, possibly from others that have done this and were in the same ocassion as I'm.

P.S. Will I still have my same number, keep my adress book, pics, and music as they were?