Microsoft has released a whole set of Wave 15 last monday which are available for everyone interested in the new versions. The version which is released is the so called Preview version, also known as Beta. So this are not the final versions of the products yet and it is not recommend to install them in a production environment.
Below you will find some links to both the downloads and documentation for both Exchange 2013 and Lync 2013:
Exchange 2013 download:
Exchange 2013 documents:
Lync 2013 download:
Lync 2013 documentats: