The Mathworks site contains some information about their wavelet panel and some simple examples of continuous 1D wavelet transforms and discrete 2D wavelet transforms .
Since you have studied and understood the theory behind wavelet transforms, the best way to find out is to go through the source code for various algorithms that others have used. To get started, consider the main functions provided in the toolbar above (just enter type functionname at the command line in MATLAB. If this is not a built-in function, you will see the contents of the file). The core of the function, I mean the basic algorithm without all the various input checks that are common.
Stanford University's Wavelab tool is also a good resource to learn (and later use in your applications when you are comfortable with this).
Finally, this is a resource I found on Google, and it looks like they have examples that you can try.