The InfoCard API

The InfoCard API is pretty straight forward (and I suspect in flux). There are only really 2 classes to pay attention to:

Microsoft.InfoCards.InfoCardClient

public static System.ServiceModel.Security.GenericXmlToken GetToken(System.ServiceModel.EndpointAddress endPoint, System.Collections.Generic.IEnumerable policy, System.Xml.XmlElement requiredRemoteTokenIssuer)

public static void Manage()

(Notice no constructor)

Microsoft.InfoCards.InfoCardTokenProvider

public override System.IAsyncResult BeginGetToken(System.ServiceModel.EndpointAddress target, System.AsyncCallback callback, object state)

public override System.ServiceModel.Security.Tokens.SecurityToken EndGetToken(System.IAsyncResult result)

public override System.ServiceModel.Security.Tokens.SecurityToken GetToken(System.ServiceModel.EndpointAddress target)

public InfoCardTokenProvider()

public override bool TryApplyIssuedTokenParameters(System.ServiceModel.Security.IIssuedTokenParameters parameters)

public override bool WillGetTokenCompleteSynchronously(System.ServiceModel.EndpointAddress target)

Besides that, it's all exceptions:
Microsoft.InfoCards.InfoCardException
Microsoft.InfoCards.NoDefaultCardException
Microsoft.InfoCards.ProvisioningCommunicationException
Microsoft.InfoCards.ServiceNotStartedException
Microsoft.InfoCards.StsCommunicationException
Microsoft.InfoCards.SuppressUIFailedException
Microsoft.InfoCards.UndisclosedClaimException
Microsoft.InfoCards.UnsupportedKeyGenerationTypeException
Microsoft.InfoCards.UntrustedRecipientException
Microsoft.InfoCards.UserCancellationException

A few other intersting things show up in the Indigo APIs:

Support for SAML, Kerb, X509, UserName, Windows, and WindowsUserName Tokens

Looks like support for April 04 and Feb 05 versions of WS-Trust