It's perhaps worth pointing out that wxWidgets 3.0 hasn't been released
yet (which was unsurprisingly also true when the original ITP was filed
over 3 years ago). Upstream are hoping it'll be released in early 2012,
though they're also still adding substantial amounts of new code, so
it seems probable that deadline will slip.
Also wxWidgets isn't GPL, it's released under the "wxWindows Library
License".
Cheers,
Olly