via http://ps3.gx-mod.com/modules/news/a...p?storyid=2901

PsDev offers a handy tool for designers XMB themes since it allows you to create and preview your theme under development.

"PS3 XMB Theme Emulator" is essentially a tester theme. After installation, you will find a folder containing the images Two XMB to change. Icons must be in BMP format 64 * 64
The bottom should be in BMP format 640 * 480 Once your theme prepared, place your icons in the XMB and run Two Ps3 XMB Theme emulator.exe. A preview will appear.