On the 2.43 RC1 or CVS version there is a button in edit mode “use snapping or gears Shift Tab”.
I have not been able to figure out what that does. I could not find any information on it wiki, does anyone know how to use it?
Thanks.
Turn it on select some verts/edges/polys go into grab mode (GKey) and then hold the CTRL-Key and move your cursor over the vertex you wanna snap to… 
PS. Here’s a post about snapping when it first got added http://blenderartists.org/forum/showthread.php?t=84807