How to save my contacts from my iphone to either itunes or iclouds?

My iphone camera came with defective flash and one of the "genius" at the Apple store told me that they can give me a brand new iphone. I want to do this because I want to be able to take nice pictures at night or when it is dark. He also told me that I can back up my contacts to either itunes or iclouds or something like that. However I do not know how to do either one of those options (itunes or iclouds) so can you please tell me step by step how to do this? Thank you and the best answer will get 10 bonus points

I also have a Macbook Pro but I don't know whether I have what they call "an itunes account" so please also let me know step by step how to create one.

How to turn a small speaker into a subwoofer?

In gonna use speakers that you connect to your iPhone, but I wanna know if there's a way to turn them into subwoofers? If there's, please explain in detail, or even better show me a video if possible?

Why won't my iPhone 4 send pictures?

I've had my iPhone for a little over a year. It would rarely send pictures. I updated it to the iOS5 recently. People are saying that's why they wot send but even before that it was rare for my pictures to send. I can send pictures to people with iPhone 4s' but not other phones. I kinda think that it might be because it's unlocked and it's tmobile. My family was saying maybe tmobile isn't updated for iPhones yet. I don't know, please help!