What wifi-dongles do you use/are compatible with the cradle, and which browser is recommended (Qtopia or GPE?)
I read the GP2X power adapter is not compatible with the cradle? Any alternatives?

No the GP2X power adapter isn't compatible.
5V, center positive adapter should do for the cradle.

There are many supported usb wifi dongles, one of the easiest to find being the nintendo wifi adapter for the Wii and DS. There are kernel modules for both the rt2570 and zd1121 (I think) already compiled and available

I still have to sort out my DNS stuff, but other than that it's worked quite well for me (I know where to look for the DNS stuff too, it's in /etc/resolv.conf, I just haven't set it up properly)

Look at the wiki it will tell you what adapters you can use and the wireless tutorial bobby martin put up is easy to follow.

Thanks for the reactions, I just needed to know, because I dont want to fry my cradle using a wrong adapter, and I don't want to waste my money on a unsupported 40-euro-dongle.