First download and install the Identity Developer Training Kit (Microsoft Download Center). The identity and access control products and services covered in this release are:
WIF has two different profiles; a passive one for browsers and an active one for web services (based on WCF). WIF can also be added to an ASP.NET web application (called a Relying Party or RP) or it can be used to generate a custom Security Token Service (or STS). ADFS v2.0 is an example of a STS.
Once you have installed the prerequisites, there are some Visual Studio WIF templates to get you going. These can be accessed from: "File / New / Web Site"
Generating a custom STS is not trivial and it would certainly help to look at some examples. StarterSTS (CodePlex) StarterSTS is a compact, easy to use security token service that is completely based on the ASP.NET provider infrastructure. It is built using the Windows Identity Foundation and supports WS-Federation, WS-Trust, REST, OpenId and Information Cards. An updated version of StarterSTS which conforms to the MVC model is: IdentityServer (CodePlex) IdentityServer is the follow-up project to StarterSTS. It's an easy to use security token service based on WIF, WCF and MVC 3. There are also some extensions to WIF: IdentityModel (CodePlex) This is a helper library that makes common tasks easier to accomplish. Have a look at some worked examples.
Claims Based Identity & Access Control Guide (CodePlex) This guide gives a very good overview of WIF and claims and refers to the labs in the training kit.
Programming Windows Identity Foundation (Amazon) An excellent guide for working with WIF and claims based identity.