Definitely be careful!
Listen to your wrists and be sure to change up your setup before you do any real damage! I also found the Apple keyboard and magic mouse to be really hard on my hands, wrists, and forearms. They look so good, but it's not really worth it.
I now use a Microsoft Natural keyboard - so ugly, I know, but made a big difference. For past few weeks I've been using the new Magic Trackpad instead of a mouse. That's taken some getting used to - I've never been a trackpad user. Before that I had a Microsoft ergonomic mouse that's shaped in such a way that you grip it more vertically than horizontally, but I think the trackpad is even better.
In general, change things up - keyboard, mouse, the height of your chair and desk. Take frequent breaks and look up some good stretching exercises.
Take care - ATM