Information Appliance Associates has released a software program for Macintosh computers that allows Sony PSP users to sync their MP3s from iTunes onto their PSP’s memory cards. It not only handles MP3s, but photos and the contacts database.
It does not support music from the iTunes Music Store however. The software, titled PocketMac for PSP, is available from the PocketMac site for an introductory offer of $9.95 USD.
More information available at Cnet.