Microsoft has just released the Dynamics NAV 2013 beta version for partners. If you’re a NAV partner, you can access the official launch portal on PartnerSource. If you’re not a partner, you can still get a lot of information about NAV 2013 from this site: Dynamics NAV 2013 Beta page on MSDN.

For more information, you can also access the links on this page Dynamics NAV Official Microsoft Sites and this one Other NAV Community Sites and Forums.