I've created a simple tool to calculate trace impedances on multi-layer PCBs and generate output files for inclusion into layout design documents. This tool can handle board stack ups to 16 layers. The tools I can find on the Web either don't do exactly what I need, cost money or are part of a layout package I don't have access to. If you have some time give it a try and feed back any comments to this thread.
Just down load the attachment and install it. It will retreive dotNet4 Client if your system needs it. I've only tested it with Win7/64 but should work fine with XP and Win7/32 also.