Got a PSP? PspWare from nullriver (now no longer trading) is a great application to sync your music, movies, photos and bookmarks from your PSP to a Mac. It also enables you to backup your game saves with ease.
With a clean interface, it is fairly simple to use and takes care of everything for you automatically using a USB connection. Movies are even converted automatically into a PSP friendly format, though this can sometimes take quite a while.
PSPWare was unofficially abandoned around 2007 but still remains a very useful application to manage your Sony PSP.