Jailbreaking need Help NewBie :D

[Wicked1]

I have an iPhone 3GS which I bough in July it has the Model Number MB I want to customize it by Jailbreaking in, but I want to be positive that I can revert the jailbreak in case I decide to.

1) Where are the instructions for jailbreaking the phone
2) Is Jailbreaking Safe and Worth it
3) Where are the restore settings to return it to factory default.

Thanks again for aeveryone's help

 

[renewed]

1.Here
2. Yes to both. Some will argue it messes up the iPhone, however if you feel it did you can always restore to stock.
3. Attach it to iTunes, click restore, click yes to update and restore and sit back and watch (or go take a walk as it takes about 10 minutes).