OAuth 2.0 delegation is included within the Azure AppFabric Access Control Service:
http://blogs.objectsharp.com/cs/blogs/steve/archive/2011/04/11/windows-azure-access-control-services-v2-rtw.aspx
But how do you actually set up an OAuth 2.0 identity provider?
In the management interface when you add an Identity Provider and select WS-Federation identity provider, you need to provide a WS-Federation metadata document.
However, when you read the documentation of OAuth 2.0 providers (i.e. http://msdn.microsoft.com/en-us/library/hh243647.aspx) there is no mention of a metadata document (Yes, I know Windows Live is included as a preconfigured identity provider). Is this something I have to write?
Update
Ok, so I've found that you can add additional identity providers using the API, see these PowerShell commands as an example:
http://blogs.msdn.com/b/vbertocci/archive/2011/05/19/adding-a-custom-openid-provider-to-acs-with-just-one-line-of-powershell-code.aspx
However when trying to add an OAuth provider, I just get an error:
Add-IdentityProvider -Type "Manual" -Name "foo" -SignInAddress "http://term.ie/oauth/example/access_token.php" -Protocol OAuth -Namespace "abc" -ManagementKey "xxxxxx"
Add-IdentityProvider : An error occurred while processing this request.
At line:1 char:21
+ Add-IdentityProvider <<<< -Type "Manual" -Name "foo" -SignInAddress "http://term.ie/oauth/example/access_token.php" -Protocol OAuth -Namespace "abc" -ManagementKey "xxxxxx"
+ CategoryInfo : CloseError: (:) [Add-IdentityProvider], ServiceManagementException
+ FullyQualifiedErrorId : Microsoft.Samples.DPE.ACS.ServiceManagementTools.PowerShell.IdentityProviders.AddIdentityProviderCommand
Another Update
The ACS Management API provides a mechanism for adding new Identity Providers (if you set OpenId as your WebSSOProtocolType), however, I can't see how you pass in the key/secret that the OAuth test server ( http://term.ie/oauth/example/ ) I'm using requires.
http://msdn.microsoft.com/en-us/library/hh278947.aspx