Will there be an amnesia dark descent 2

Indeed there is! It will be coming out Fall 2012 and is currently known as "Amnesia: A Machine For Pigs". Although it's a sequel to Amnesia, it's in a way unrelated so you will see brand new characters in the sequel and none of the old (Alexander, Daniel, Agrippa, etc.)

To learn more about it, you can visit its official site in the related links below.