This month Microsoft announced the availability of Dynamics GP 2013 demo which you can download here.
Most of the improvements were geared to improving security, integration with other Microsoft products and the Web client.
I was reading the installation guide of the web client and the requirements were pretty basic including the Web server OS which can either be Windows Server 2008 R2 or 2012. You can secure the web client by implementing SSL which you can purchase from a vendor or use one provided by IIS.
If you've installed Microsoft Sharepoint Server, most of the required steps were very similar including the required authentication.