Will jailbreaking wipe out songs and contacts on iPhone 3G?

[hrcs]

Will jailbreaking using the current pwnagetool erase all my songs and applications downloaded from the appstore on my iPhone 3G? Because it's doing a restore and if you normally do a restore on iTunes it wipes out everything.

 

[philgilder]

yes it does wipe everything
but you can restore data from a backup