What do you mean? This works great for me.
Photos and setup in this thread: http://talk.maemo.org/showthread.php?t=31117

Enjoy.

As far as the N800 goes, everything should be identical except that you need a mini-usb OTG adapter instead of micro. Search "N800 otg" there are a few sites plus ebay.

There are reports that a regular adapter is sufficient with the newest version of the OTG software component but I can not verify.

At this time the N900 does not support OTG and thus not even a usb keyboard will work. The community hopes this changes in the future.

I should also ask, what chipset does your Alfa usb card use? If it is a RTL8187L (detects as RTL8187) then you are golden, the RTL8187B is a crappier version and uses a different driver. lsusb + the model # should suffice.