Sony + Ericsson = 
SonyEricsson
They make CellPhones, including the P800.
After purchasing a SonyEricsson mobile, I found that MP3 files downloaded to it could not be set as ringtones. The manual explained that the MP3 files needed to be specially CopyRighted.
To get your MP3 files in the correct format for a SonyEricsson mobile (possibly this is only required for Vodafone?), do a Google search for Sony Ericsson DRM Packager. You should be able to find a MicrosoftWindows program that modifies your MP3 files into some DRM format.
6 pages link to SonyEricsson:
