I was issued a patent in February 2009. Another party using my claims was issued a patent in July 2009. Is that infringement?

Jeff and William have already provided you with really good information. As for copyright law, it has no bearing -- none, nada, zilch -- on this fact pattern. This is wholly a patent law issue with maybe some trade secret and unfair competition tort law thrown in (due to the access issue you mention).

One point: The July 2009 patent owned by the other fella is NOT "using" your claims. By definition, those claims are his claims. They may look like your claims, they may build upon your claims, but they are his claims. For example, if you claimed elements A, B, and C and the other fella claimed elements A, B, C, and D that is his claim -- but (as already noted) he needs a license from you to practice his invention because his invention includes yours. However, if he claims elements A, B, and D and your element C and his element D are not equivalent then he needs no license from you to practice his invention. Which does not mean that his claim should have been allowed, it only means that -- as of now -- that claim is presumed valid. You can, as noted, try to persuade the Patent Office or a court to invalidate his claim.

In short, see a patent attorney if his patent causes your business any money.

It is not infringement, per se. The short answer is that it is hard to tell with the facts you offer here. Someone can take a patented subject matter and design around it, which it sounds may have happened in this instance. I am not sure how the person filing the second patent application had access to your confidential patent application—if it were confidential, how did he or she have access? If the application were already made public, then there is nothing confidential about it, unfortunately. If the individual had access to confidential information of yours, you may have other recourse. Patent design-arounds happen all the time.

You should discuss the specifics of this matter with a knowledgeable attorney in order to develop the best strategy for protecting your rights. Even if the other party successfully designed around your patent it does not mean you may not have rights.

Please note that this information is for informational purposes only and is not legal advice and should not be construed as legal advice. Nothing herein is meant to create an attorney-client relationship.

the important thing to appreciate in this circumstance is that just because the PTO issued the second patent, the other party does not have any rights to infringe your patent simply because they now have their own. If this other party is a competitor or somehow hurting your bottom line you would be advised to speak with a patent attorney about your options.

If the subject matter of the two patents overlap and the examiner of the second patent was unaware of your patent, you could potentially file a request for reexamination of the second patent using your patent as prior art.

There are other options such as the development of cross-licensing agreements which you also might want to consider.