It's possible to use the Nintendo Wifi USB dongle as a soft AP. That means that you can use it for any device; no just the Wii and the DS. In my case, I'd like to use it with my PSP.
No matter how much I try, though, I can't get it to work using the guide you can find. I get as far as having my PSP to see an access point, but it never manages to connect, with or without security enabled, open or shared, IP address on the same or different subnet, and so on.
Here is one instance of the guide: http://forums.afterdawn.com/thread_view.cfm/390312
I have no idea what could be wrong, because the PSP's error messages are too generic. It just tells me that it couldn't connect and to check my security settings.