When I started with Ubuntu Studio 11.04 the other month, it had no
trouble detecting and installing my Wifi stick. I soon got onto the
Internet.

Notes:

1) My original USB stick (Sitecom WL-344) proved incompatible. I
replaced it with a preceding model (Sitecom WL-302), and that worked
as expected. After updating my system, even the WL-344 works.
Anyway, it is the chipset inside the stick that seems crucial.

2) This week I had an experienced friend help me to get this Ubuntu
computer connect with my Windows network. For whatever reason, he has
only managed to have my Windows computers access the Ubuntu one, not
the other way round.
The graphic Samba tool proved insufficient to achieve this, but he
knew (and preferred) how to manually edit the configuration files.