While there are no specific exclusions for patenting software or methods that are implemented as computer software or a related product, it can only be patented if the 'substance of the invention' has a technical character. This can be tricky to determine. Before you apply, ask yourself: Is the invention new and novel?
If you want to protect your software through the patent system, you must submit a patent application. Your application must describe your invention in detail (the specification), should include drawings, and must truthfully name the inventors of the invention.