GitHub is a code repository and a code repository is a system where you check in your code as it's developed. It allows multiple developers (though it's good tool even for a single developer to use too) but it also offers other features like change tracking (you can pull out all of the code from a certain revision or date) and because most simply use a type of url to access you can usually set it up to be available from anywhere, so long as you know the url and your login credentials. One of the nice things about GitHub is that it's a free service, the downside of GitHub is that your repository is public to everyone (at least read access is public, checking code in might be more restricted).
Originally Posted by gbalcom
Currently using: VS 2010 Ultimate on Win7 Ultimate x64.