Good article on screen to print matching
My friend David Saffir has written a good, simple article on common issues with getting your screen image to match what is coming out of your printer. Worth a read on his blog.
Color Management
Calibrating an iPad
David Saffir has written a great little article about calibrating an iPad using the Dalacolor Spyder 3 and some software for both the computer and the iPad. David says it better than I can, so read it here.