Right click on your MVC Project. Go to Properties. Go to the Web tab.
Change the port number in the Project Url. Example. localhost:50645
Changing the bold number, 50645, to anything else will change the port the site runs under.
Press the Create Virtual Directory button to complete the process.
See also: http://msdn.microsoft.com/en-us/library/ms178109.ASPX
Image shows the web tab of an MVC Project