My wife and I are a somewhat unusual couple, in that we are both wormophiles. We deeply appreciate what worms do for our soil. In fact, whenever we see a worm in distress, we rescue it by providing a free ride to the compost pile.
Maria was recently turning over the compost, and she was greatly impressed with the number of worms taking up residence there. I can't tell you with what glee she informed me of the abundance of "wigglers" in our compost pile. And with good reason: more worms means your organic matter will be broken down faster and turned into usable compost.
As Kelly Burke notes, though, some folks find worm castings in the yard unsightly. But Kelly casts a positive light on worm castings -- at least when present in moderation. And if your mole hill of worm castings is becoming a mountain, About.com's Guide to Lawn Care has some solutions for you to implement in this article.