Hi,
As mentioned, best to use CSS and div tags, but the option to set absolute positioning in VS2008 is under Tools>Options tick the box at the bottom to "show all settings" then expand HTML>CSS Styling the bottom tick box sets positioning to absolute.
I hope this helps, if it answers your question, don't forget to mark it as such for those who come afterwards.
Regards,
Gareth Chidgey
Website Design Director
Gaia Website Design Limited