There are lots of open source and dynamic language choices but without knowing the direction you wish to go or what appeals to you, it’s difficult to answer.
Microsoft offers some great free training for beginners. They recently opened a <a href=”http://msdn.microsoft.com/vstudio/express/beginner/”>Beginner Developer Learning Center</a> that is pretty nice. There are two tracks — one for Web development and one for Windows development.
I’m sure other readers can improve this answer by adding information about free online training with their favorite languages. Good luck.