this torrent contains a .ipsw file. the file has been PWNed and works with any operator and also contains installer.app and Cydia.
to restore this .ipsw file on your iPhone 2G simply open the iTunes (ver. 8 or higher), hold the Shift key and click on RESTORE button, browse for this .ipsw file and then let the iTunes restore it on your iPhone.
please note that ONLY IPHONE 2G IS SUPPORTED!