UPDATE - 6/19@10:11AM: The issue is actually not yet available for purchase; it's only available for pre-order right now and will release next Wednesday, June 25th. According to Boom! Studios, the graphic novel is supposed to be on a monthly release schedule but has seen several production delays (thanks Rob S).
The third of six issues of the graphic novel version of Clockwork Angels is now available for pre-order and will release next Wednesday, June 25th. In addition to the standard cover that is available in comic and book stores, there is an exclusive, limited edition cover available via BOOM! Studios and the Rush Backstage Club. The first issue of the graphic novel was released back on March 19th and there were a number of different covers and subscription options made available as described in this post. The second issue was released on April 30th and is also available in both the standard and limited edition covers.
[Clockwork Angels graphic novel issue 2 releasing this week]
[Kevin J. Anderson on the Clockwork Angels graphic novel]
[Clockwork Angels graphic novel issue #1 preview]
[Clockwork Angels graphic novel cover art updates]
[Clockwork Angels graphic novel cover art preview]
[Clockwork Angels graphic novel preview, new interview with Kevin J. Anderson and Neil Peart]
[Neil Peart and Kevin J. Anderson talk Clockwork Angels graphic novel in new interview]
[Kevin J. Anderson talks Clockwork Angels: The Graphic Novel in new interview]
[Clockwork Angels: The Graphic Novel now available for pre-order]
[Kevin J. Anderson, Neil Peart talk Clockwork Angels: The Graphic Novel in new USA Today article]
[Clockwork Angels: The Graphic Novel from Kevin J. Anderson coming April 2014]