if i restore the iphone i have to backup my data..

[bo-waleed]

how can i backup all my music,apps and contacts ?

 

[Bandolier]

iTunes, click on your phone on the left, hit Info, check the box to sync Contacts with whatever service you want to sync it with. Hit apps, make sure sync apps is checked, right click on your iPhone and hit Transfer Purchases. Under the library part of the left side bar, hit Apps, make sure your apps are there.

Right click iPhone, hit transfer purchases again for good measure, sync, back up.