This is what I have been playing with today. My Christmas present - White Serger 2500. I was using the threads it came with - I will be attempting to thread the thing some other time. But I tried the basic overlock stitch with 4 threads as well as adding elastic to the fabric. You can see what the edges look like below. Perfect.

This is sooo much easier than with a sewing machine! Now, don't get me wrong - the sewing machine is not going anywhere, but for knit fabrics (like the one in these images), adding elastic, picot edges... I will be using this puppy. I have a great Singer, but it just does not handle knit or stretchy fabrics well. It is supposed to be able to do a double needle, and it has another single needle stitch for stretchy fabrics - but whatever I tried it stretches the fabric too much while sewing and the end result is not pretty. This will work very well.

So what I made? Two changing pad covers - I cannot really model them because the old changing pad is in the trash, but, apart from cutting the fabric, it takes maybe 15 minutes to serge the four corners and add elastic around. And the edges are all finished nicely. Can't beat that!