Though it's very easy, getting the skin off is the most time consuming part. Here's the trick though.
Start by making a small "X" or simply poking a knife in the bottom of your tomatoes.
Dunk them into a large pot of boiling water, just a few at a time. Within a minute the skin should split from where you broke the skin.
When skin breaks, remove them from boiling water immediately and submerge them in ice water to draw the skin back even farther.
Use your hands or a knife to crush or cut the tomato flesh into small pieces in the colander. This helps to eliminate some excess juice.
(**Update: Check out my related post on How NOT to Can Tomatoes**)
Enjoy the flavor of sun ripened tomatoes all year round.