GPL v2+, GPL v2, GPL v3, LGPL v2, LGPL v2+ ?

[Cyrille Berger]

No you can't convert BSD to GPL, but you can use BSD in closed source software 
and never release any change to it. You can't convert GPL3 to GPL2+. 
LGPL(smthg) can convert to GPL(smthg) that's the only "radical" change you 
can do, other than that in some occasion you can increase the version number 
of GPL. So
LGPL(smthg)->GPL(smthg)
GPL2+-->GPL3

and that's all.
-- 
--- Cyrille Berger ---