As I pursue the path of becoming a programmer, I would like to build up a portfolio of projects I worked on at my current job so that I can eventually get programming work elsewhere (either as an employee, contractor, one man consulting shop, etc). Some of these were things I coded myself, others I was instrumental in the architecture, design and functionality (ie, not as a programmer but more of a BA).

How do I show the work that I have done to others on the projects that I have produced for the company I work at? This is all internal software, so it's not something that the outside world would be able to use, and some of our products contain proprietary financial market tools and it would not be prudent to share those with the outside world. My guess is that screenshots would definitely be out of the question, as well as functional descriptions of the software.