Being that your new to the job and the area of expertise (as far as professional jobs go) I think they'll understand to a certain degree that you might not 'get' everything right away; So don't be discouraged easilly!
If they give you a tour of their facility and introduce to people make notes on who you might like to sit down and discuss the work environment with. It would be a nice idea to get suggestions/views from a variety of employees that will be working in the same area as you. If a tour isn't one of the first things they give you, I would suggest it be the first.
Ask for some technical documents or code that you should read to gain some familiarity their completed/on-going/planned projects in order to adapt to their particular programming style and way of thinking. Don't hold of asking any questions (after doing a reasonable amount of searching around, of course).
Plan in some self-learning. Sit down and watch webcasts (if available) regarding the particular applications you're using to develop. Whitepapers, technical books, etc. would be good also. If you have regular meetings, don't be shy and offer some of your insight if possible. Even if it won't be a direct help to the problem at hand, it may show them that you aren't afraid to be open and share your knowledge whenever possible.
Make friends with your superiors and win over your co-workers. Try not to be set in your ways. If you believe your way to be superior and should be used in a current project, write a paper/essay detailing why. You may get bonus points, even if they decide to not use you idea anyways.
Most importantly though (IMHO) is to always be willing to learn, even if you have no interest or use for something currently. It may become useful in the future or you may be able to suggest a particular solution for problem elsewhere down the road.