If you register at teh USA offsite, there is a very handy training planner on the tools. You can change the skills of your player, and it will give you a rough prediction of the salary, as well as the cap number from the Josef Ka's coefficients.
See my sig for how to. Lots of good stuff at the offsite forums, and other very helpful tools.
Sorry, but is there a globally accessible link to this? If it's not on hand, don't go out of your way.