Sony has launched 'Portable TV' for the PSP, initially offering around 100 free downloads.

The P-TV service, launched in Japan, uses Sony's ISP company, So-net. Initially the service will offer downloadable videos of independent movies and trailers, but should soon offer premium content, such as TV episodes, movies and music videos for a fee.

The service takes advantage of some of the media playback updates included in the PSP Software version 2.0, offering higher quality H.264 encoded videos. Content is expected to weigh in at 256MB for 30 minutes of video, with pricing yet to be announced.

Although users will be able to browse through what's on offer from the P-TV service, it is unclear whether or not the video files can be downloaded directly onto the PSP or if a PC will be required.