something very important is to be careful to describe your software as a mechanism or a method and not as algorithm (mathematical formulae cannot be patented),

something very important is to be careful to describe your software as a mechanism or a method and not as algorithm (mathematical formulae cannot be patented), that functions as a mechanism. You can either give source code or flowcharts. I am not sure if it's ok with object code. Have a look at the ICQ patent and other known patented software, to see how claims should be written. Applying on your own online at uspto.gov or epo.org could really cost you not much. Or try legalzoom.com. A lawyer will be helpful if you don't know how to write your own claims. *update If the software is an early version you should consider filling a provisional patent, which costs less. This would give you 1 year to perfect it. Though you should be careful because if your description in the provisional is out of scope and doesn't match with the patent application it would not server any purpose.