Have you added your host name or IP in "GPEDIT" i.e.Group Policy and enabled to use fresh credentials?
Please follow the step if you might have missed something.
(http://www.ifunky.net/Blog/post/How-To-Enable-PowerShell-Remoting-(WinRM).aspx ,
They have enough information to get started. Sometimes if everything is enabled its a best idea to restart remote management services.