To quote: I've hooked up Showtime to the video decoder libraries already present on the PS3. This will accelerate h264 (Up to level 4.2) and MPEG2 video decoding so it can play up to 1080p content.
If you want to make sure that the Cell acceleration is actually used you can press L3 during video playback to see the status window. Make sure that the video codec mentions (Cell) at the end of the row. Just like in this screenshot.
1. Playback of video and audio
3. Unified search
4. View photos and images in slideshow mode
5. Live TV streaming from Tvheadend
6. Spotify integration
To quote from his page linked above: After about a month of hacking I'm happy to announce that Showtime now can be run as a native "homebrew" application on the PS3. See PS3 usage guide for more information of how to get started.
If you have any questions please use the PS3 forum on this site.