Welcome to the OpenCV world! It is one of the most colorful and enjoyable parts of the computer science!
There are many places to start from, each with its own strong and weak points. I will list some resources here, letting you choose how to start with them. All provide a gentle introduction to both OpenCV and image processing techniques.
But, before going this way, you should make sure you have at least basic understanding of C/C++ (this is the main language for OpenCV, and most examples/tutorials use it, but there are also Java, Python and unofficial C# bindings). You should know about memory management, pointers, data structures and objects. Basic knowledge of STL will help you.
Starting points:
Online documentation and tutorials. Here is where you learn basic installation/configuration, and then move on to actual image processing with this great tutorial list. Do not forget to explore the opencv/samples folder in your local installation folder
"Learning OpenCV", a book by Gary Bradsky and A. Kaehler. It offers an in-depth voyage thru image processing, and after completing it you'll be well equipped for even complex tasks in the field. It is similar in presentation and level of difficulty to university courses, but offers a gentle intro, so you should not be shy on it.
OpenCV Cookbook, an easy-to start book with nice examples. It is somehow easier to follow than the previous one, but it offers much less in-depth discution.
If you are already familiar with image processing (with other languages/tools like Matlab/Octave, etc) and also have a good programming experience, the reference docs and the opencv/samples should give you a kick-start in OpenCV
Last, but not least, do not forget to explore some other online resources, when in need: