There is nothing yet as Sony are not really keen on Home Brew stuff. But if they want to really embrace user driven content, as they claim they do, they need to release a tool similar to XNA. Actually as a for starters, they should port SDL to the PS3 and PSP Native ( it already works on PS2 Linux ), that way anyone writing for Windows, Linux and MacOS can also target PS3. This would be way better than XNA which only allows XBox 360 and Windows at the moment.