Hello Andrew,
> Can anyone recommend an 802.11g USB wireless adapter which is supported
> by the Linux kernel?
Yeah, it's a pity that so many vendors don't care about Linux support.
But there are some cards which work fine with Linux native.
I think the best thing is to buy a card with Prism GT chipset. This is
best supported chipset for Linux. Older Prism 2/3 chipset ist only for
802.11b.
My card has a RT2500 chipset. This works fine, too, and is easy to
install. You may be free to buy any card with the RT2x00 chipsets...
Have a look at the project page for details.
http://rt2x00.serialmonkey.com/wiki/index.php/Main_Page
To find out which card has which chipset go to
www.linux-wlan.org best.
Hopefully this is helpful for you
Daniel Böhmer