I have written a new piece of software for a service, that i found out later, is patent pending.

There's no getting around the fact that, since you now know of the patent, you need to hire a patent attorney to review your software's processes to consider whether your software infringes the patent. If you don't, and you then make your software available, you may be sued and found to be a "willful infringer."

I suggest that you read the article at http://papers.ssrn.com/sol3/papers.cfm?abstract_id=994372 which wlll give you a decent background on software patents.

Note: it is quite common to "design around" software patent claims so all is not lost. Moreover, the US Supreme Court will (in about six - nine months) issue a decision in a case called Bilski that will address the patentability of business method patents -- though that will come too late for the program you've just developed. Keep an eye out though because it will likely dramatically curtail these types of patents which could help you in the future. Good luck.

If this is a business interest for you. Hire an attorney to draft do an infringement analysis and draft an non-infringement letter. These could both help you market your software and possibly save you a lot of money should you ever lose an infringement lawsuit.

However, infringement opinions for patent applications are tricky in that there is no patent granted but you might be liable if one is granted. Further, it is possible that their patent application will be so amended before the it is granted that what they applied for and what they obtain are two different inventions, and it would really be necessary to keep an eye on the application as it is prosecuted to make sure that the infringement opinion reflects material changes.

As to breadth of the patent application, it is important to recognize that there is no requirement that a patent owner manufacture or practice the invention as described in the patent. It is a common patent drafting strategy to protect an invention by claiming alternatives and prevent competitors from creating an easy work-around.

If the claims seem too broad to you, the USPTO examiner might feel the same way. It is rare for a patent to be granted on the original claims. The applicant is almost always required to submit narrowing amendments to the claims. If you choose to disregard the sound advice to hire an attorney, you can investigate the current status of the the application by using the USPTO's Public PAIR service. This database include all of the history of the patent applicaiton, including any preliminary rejections. This might provide you with insight as to whether the applicant will successfully receive a patent.