Video is not simple. It has fairly high bandwidth requirements that are just beyond what a 16Mhz Arduino with limited memory can handle.
Rather than getting a web cam, get a camera that outputs composite video directly, such as the cameras made for car backup systems. You should be able to hook this camera straight to the Myvu, which appears to have a connector for the yellow RCA plug for composite video. Here is the first such camera I found on ebay: 170º CMOS Car Rear View Reverse Backup Parking Camera Waterproof Wide Angle for sale online | eBay
If you have an Uno, you might be able to use the Video Experimenter's shield to overlay some basic text information over the video stream. It won't work with Leonardo or Mega processors. I bought one a few years ago, and never used it. As I recall, the source available was made for pre-1.0 Arduino libraries, and you needed to make some minor mods to get it to compile: Video Experimenter: Arduino shield that lets you do all kinds of experiments with video