Authentication and authorization - new to security

Need to develop a Web application that will be used to authenticate and authorize internal and external users to log and then re-route to web applications for the organization. The login application should be able to provider smooth integration with any开发者_运维知识库 future applications that needs a secured authentication.

Should I be using WIF - Claims based Identity/ADFS or asp.net Role membership provider to develop this app.? Or is there any other approach which will help achieve this?

I've been working on an asp.net site with WIF for several months now. I like that WIF is very flexible, but the documentation is poor. Check out the discussions on SO about WIF.