UMDumper is the popular UMD dumping software authored by PhonicUK in C. It is the only current dumper for 3.xx kernel that will rip directly to CSOs without requiring any extra steps. It is also the fastest of the dumpers out there due to its use of multithreading and asychronous IO. Supports both fat and slim PSPs.

Changes:

* Automatically correct invalid filenames
* Reworked CSO Support
* CSO Levels 2-9 are back!
* CSO Speed improvements!
* Mp3 Playback while ripping!
Press Square to toggle playback. Simply replace Music.mp3 with the song of your choice. Must be 6MB or less.
* Even more international versions
* Improved memory management
* Misc minor bugfixes
* Fixed crash when starting dump in CSO mode with insufficient free space.
* Improved performance for PSP slim
* Eboot image and music!

http://forums.qj.net/f-psp-development-forum-11/t-update-umdumper-030d-released-mp3-playback-cso-improvements-140266.html