On EC2 (and other clouds that support userdata), we can pass a Powershell/Batch script that sets things up for us on a Standard Win 2k8 Image.
Here is the script:
<powershell>
winrm quickconfig -q
winrm set winrm/config/winrs '@{MaxMemoryPerShellMB="300"}'
winrm set winrm/config '@{MaxTimeoutms="1800000"}'
winrm set winrm/config/service '@{AllowUnencrypted="true"}'
winrm set winrm/config/service/auth '@{Basic="true"}'
</powershell>
This should setup winrm for you pre-bootstrapping.
And here is the ec2 command:
knife ec2 server create ..... --user-data enableWinRM.ps1...
Let me know if this helps!