Microsoft is giving away versions of its software... Visual Studio 2008 Professional Microsoft Expression Studio Windows Server 2003 Standard Edition XNA Game Studio https://downloads.channel8.msdn.com/ Only if you are a college student though.
They are full copies of the product, simply made free by microsoft to help young developers build their skills to broaden their careers future.
I am sure you will find that Microsoft are allowed to distribute Microsoft software for what ever price they want including free. They also do the Home User Program which allows corporations to give their employees to have Office and other applications the corporation uses to be installed on their home personal PC even if there is no work element involved. The element to check is the licensing, with HUP and the normal Student editions the license is only valid whilst your an employee/ student and as soon as you leave you should uninstall or buy a full license. It may well be the same here, they are only technically legal whilst you remain a student and once you leave they arent but as I am not a student I havent spent time reading the details of the offer.