UD-CPS2 Supergun
You can replace your CPS2 A-Board supergun with the UD-CPS2 ready with usb ports to connect XBOX 360 and PS3 controllers. Power supply is integrated inside and it works with an off the shell laptop charger. It also has a starndard off the shelf Playstation A/V port cable output.
UD-USB Decoders
If you already have a supergun or any DB-15 compatible device you can integrate it with the UD-USB Decoders so you can plug your XBOX 360/PS3 controllers. There are two versions: the 15 Pin D-Sub version and the Terminal Block version