I have a Conitech Dakota TA USB based upon WINBOND IS89C35 chip. The drivers are freely available at this address: http://www.conitech.it/conitech/ita/risorse.asp?cod=CN402USB It works fine under Fedora 4 i386, kernel 2.6.11, but it seems impossible to have it working under Gentoo with gentoo-sources 2.6.21-r3 x86-64. It would be wonderfull having it under portage or at least having it working under gentoo systems. I know that some devel at Red Hat (Dave Jones <davej@redhat.com) and at tuxdriver (John W. Linville <linville@tuxdriver.com>) have taken a look at it and maybe can help in having it working. Conitech may help too <supporto@conitech.it>.
A new driver for Conitech Dakota TA USB based upon WINBOND IS89C35 is actually in staging for the next kernel release. On Linus' git repository the driver is under "Device Drivers" -> "Staging drivers" -> "IS89C35 WLAN USB driver" (CONFIG_W35UND). The driver is actually under development but I think this bug can be resolved upstream.