The version numbers between Windows and Linux are related - the first two digits, at least...
The latest beta I've seen so far is 4620, dated 2003-09-29, but I don't think Nvidia would be pleased if I would post a link... - this beta seems to be quite stable, but maybe there are some issues with it that keep Nvidia from releasing?!
And I don't know if the FX5700 or 5950 is supported by that beta, but there is at least one very nice improvement in 4620 - I think a lot of people will be happy about it... ;-)
"Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music."
-- Kristian Wilson, Nintendo, Inc, 1989.