I'm struggling to find much about the language QCL, rather than about quantum computing itself.
Is there anything out there like that? It doesn't have to be free.
My master thesis in computing science deals with computational and architectural questions of quantum programming and illustrates the design of quantum algorithms in QCL. For readers with a CS rather than a physical background, this book also features a brief introduction into quantum physics in general.
My master thesis in theoretical physics about QCL. Besides a general introduction to quantum programming and a description of the language, a complete QCL implementation of the Shor algorithm is presented.
My PhD thesis on structured programming languages for quantum computing (latest revision Jan 9 2009).
This paper from the QS2002 conference describes classical concepts in QCL, including new features like conditional operators, quantum conditions and quantum if-statements. The print version appeared in the International Journal of Theoretical Physics 44/7, pp. 943-955, 2005.
Also, check out these video lectures on QCL by Macheads101: