Hey showard.

Here's a few suggestions: (1) calibrate your monitor, (2) talk to the printer—find out if their 'in house' people use a particular colour profile for their images. (3) Make sure your pics have good white and black points and maybe bump up the contrast. Remember that the screen is just a representation, what you get from the printer shows you exactly what you've created (maybe too late by then!).

Hope some of these suggstions help...