The Pixelink API is currently a set of at least 29 functions, but which ones are most important?

If you have more than one camera connected, you'll need to look at PxLGetNumberCameras. PxLGetNumberCamerasEx may also be useful if you are using GigE cameras.

To connect to, and disconnect from a camera:

To see what the camera is capable of, and how to configure it:

Functions that may be useful to get an image from the camera include:

And finally, Here is a flowchart of how the functions are typically used.