I am trying to get started in development of my website and plugins using Umbraco. When I download the binaries from Codeplex, the installation and running of the website works fine. When I downloaded the source code, All I get is a login screen even when the web.config files are the same. Am I doing something wrong or is there something I missed.
The path I use to map IIS to is
branches\4.1.0\umbraco\presentation
You need to compile the source code to get it to work.
To be honest, you shouldn't need the full source unless you really want to start hacking around in the core (which may cause you problems with future updates) or you want to see how stuff works. The Umbraco framework is pretty extensible, I've not found too much so far that I couldn't do without having to touch the core source.
I had a similar issue when running the source and that was that the hashing of the admin password did not work. So i debugged it to see what value was expected and then changed it in the database.