I believe it is the same thing.
Jailbreak your iPhone
you go on a website called jailbreakmatrix
No
Yes but your iphone has to be jailbroken and have Cydia.
click on Restore in Itunes
No. These are apps that you get when you jailbreak the iPhone.
If you jailbreak your iphone, you can get a package called "frash" from cydia
There is no way to do that. If you jailbreak your iPhone there is an app on Cydia that does that.
Yes, if you restore your iPod or iPhone on iTunes it will delete Cydia. The restore function on iTunes restores your iPod or iPhone to its previous settings.
Don't download loads of apps. Cydia alone will most likely not crash your iPhone, but installing many apps increase chances.
No
From the Apple app store or from Installous via Cydia.