1. Get a copy of the PC UT3, however you would like to do that is up to you.
2. Open the said PC map in the UT3 editor
3. Hit file save as, then save the map to Unreal Tournament 3/UTGame/Unpublished/CookedPC/CustomMaps
4. Run the UnrealFrontend.exe found in:
C: Program files/Unreal Tournament 3/Binaries
5. Hit the Cooking tab
6. Check the Packages have changed box
7. Set the language to int
8. Set the mod type to map
9. Use the file name of the map in the filed above the import map tab
Do not add the file type just the name!
10. Hit Cook
11. A window will pop up asking you to name the file, use the name of the file a gin But add PS3 to the end of the name.
12. There will seem to be lots of errors, never mind them.
13. After cooking, a window will pop up asking you to look over your maps INI.
14. Look over the ini if you like, then hit OK.
15. A pop up window will prompt up asking where you would like to save the file.
16. Save the file to a anything that can be plugged into the PS3 where "PS3" is in the root of your external drive... it must be in a very specific folder structure: PS3\SAVEDATA\BLUS30086-MODIMPORT\USERDATA.JAM
17. Import the file to the PS3 & play the map you want!