X11 Style Copy on Select in Windows?

I've never tried it, but the True X-Mouse Gizmo looks like it will do exactly what you want.

I tried the True X-Mouse Gizmo and it was cool but the lack of configuration options didn't work for me either. AutoClipX is another solution:

http://12bytes.org/software/autoclipx

It's not free, but he's only asking for $5.