Roms are just generally something a chef will make that runs a different winmo system on your phone.
To change the os to windows mobile 6.5 you need to enable the bootloader and flash a rom to your phone. There are many many tutorials on how to do this.
As for android, you just create certain folder structure on your memory stick and run haret.exe to boot android. There are many tutorials on how to do this as well.
Hope that helped a little bit
