One the windows 2008 server capabilities are to act as a router. This service was already enabled on former windows operating systems.
To accomplish this issue, you should take two simple steps: step one is to enable RRAS service under the windows 2008 server and step two is to configure it as a router for local clients.
Step one: enable RRAS service

1.Go to start < programs < administrative tools < routing and remote access
2.The RRAS console should come up < right click the server name on the left pane < press the ‘configure and enable routing and remote access’.
3.Use the wizard to enable the RRAS.
4.Choose ‘Custom Configuration’ < click Next
5.Choose ‘LAN routing’ < click Next
6.Click ‘Finish’ and start the RRAS service.

If you want to add IP address to the router interface do the following:

1.Open the RRAS console <expand ‘IP Routing branch’ < click ‘General’
2.On the right pane <  right click the interface you want to configure < choose ‘Properties’
3.Configure\apply the IP address, subnet mask and gateway of the IP you want for that interface. You can also add static route to that interface by Clicking ‘Static Route’ <  right click the right pane < choose ‘New Static Route’