I am curious if the US Patent Office has ruled on whether or not this patent is even valid. There was a patent dispute supposedly filed by the International Virtual Tour Photography Association (http://ivrpa.org/patent), and the dispute was backed by several industry players. Apparently, the patent should have never been approved because there was a large and sufficient amount of previous work that was documented over the years showing this technology in full use by the general public prior to the patent approval.
George White provided a concise response that should serve as a general guide to similar questions. It would be nice for this board to have routine responses distilled out, perhaps in a decision-tree format... George's well thought out answer could serve as the appropriate process step for patent on invention granted, re-exam started, resource links. This will undoubtedly come up repeatedly.
The issue of validity of patents, particularly of how well the USPTO has reviewed prior art, judged what is obvious to someone versed in the art or otherwise uniquely patentable is ground for much discussion. No patent system can become perfect. Patents of questionable merits exist. The task often is to understand how the 'system' works on paper and also in real practice and then determine how you/your company works within it. This starts from understanding your own capabilities, willingness to pursue the alternative IPR strategies including defensive/pre-emptive patent strategies.
As documented at the site the link in your question points to, this was a subject of large push-back. There was a re-examinaion process started that is still pending and it looks like the one law suit has been stayed waiting for the result of the re-exam.
This can be looked up and followed in the USPTO Public PAIR. If you up an application or patenting PAIR there is a continuity tab that will give you information and links to it related parent and child applications. A reexamination proceeding gets is own serial number that the system uses like an application number.The reexam serial # in this case is 90/011,974 and two of the dates things have happened are:
01-10-2012 Notice of Reexam Published in Official Gazette
And the last thing in the case was a response by the patent holder:
12-03-2012 Response after Non-Final Action