I wonder if there is anny possibilities to use regular usb devices such as keyboards and joysticks using the gp2x onboard usb port that is used to connect it to the computer. Ofcource one would have to build an adapter to make regular usb cables work. but is it even possibel with the software and if it is is it just plug or play or does it require some insane ninja tweaking ?

I don't think so. That's what the EXT port is for.

The port on the side of the 2x is a "client" port, used to connect the unit to a host.

The EXT port can be converted/used as a USB Host, for things like keyboards, mice webcams (as long as they don't draw to much current).

If you wanted to get all "ninja" on it, I guess you could add the needed hardware inside the unit and wire it to the side port (although you'd have to remove the current connections)

There are a couple of examples of people adding a USB Host port to the 2x, although that requires quite some skill with a Dremel and a some electronic skills

If you want to buy a cable that just does USB, get one from here. (Scroll down to the 9.99GBP cable.)

That cable is bad, don't know why but it just seems to work with very little devices without having a power supply for the devices.

That's probably because the GP2X can't output enough power to run them- a powered USB hub is probably the best solution

Partially, yes. But the cradle works with many more devices, for example, using the Host cable my wireless keyboards receivers' LEDs will dimm, but with the cradle (without power supply) It lights brightly up, and can even power a mouse receiver and memory stick + gamepad at the same time without requiring power supply!
You gotta admit, quite impressive.

I recently noticed that with mine too. I thought it worked fine at first because it worked unpowered with a usb stick but i tried it with the simplest usb pad I could find and a usb mouse and neither worked unpowered. I'm sure that i'm doing something wrong though... does it have something to do with the battery's?

I think that's due to the host cable being limited to 100mA.

Hmmm... That's pretty odd. Perhaps, if you connected both of the GP2X's power outpit lines in parallel, then you would get a decent power output. (The Wiki has a pinout for the EXT port.)

Hmmm. Your's should be a 5th revision too... (5th revisions were produced after July/August 2006, and put out 5v through the EXT.)