Dazzboard is a free online media manager that supports all mobile devices, including cell phones, mp3 players and media players on a Windows PC). You can use it to
* Connect your portable device and PC
* Transfer your photos, music and videos
* Download content from the Web to your device
* Upload content from your portable device
* Connect your device and Social Networks
It's still in the beta stages and you have to request an invitation to use it. You can also view a video about how it works at its site here.