This has probably been posted before, but I\'m not sure what search terms to look for!
Quick explanation.
I have code that is shared between a few projects. This
Microsoft has been supporting an open source project which comes built into VS now, its called NuGet, you can output your shared project as a nuget file and consume it in your other projects.
It will actually deploy all the files you specify in the package upon build.
This is how .Net supports dependencies now. You will notice that even things like EF come through NuGet packages. You can even host it for free on places like MyGet.org I use this and it works quite well.
http://nuget.org/