This is odd, coming from the likes of me. I don't like job descriptions. I never have. If I could rewrite my job description, it would simply say, "get the work done." Period. But I have to know what work I need to get done, so job descriptions have an initial value, plus the keep us in HR in business. It isn't exciting or sexy, it's administrative. And I am always looking for ways to alleviate high administrative work. That's why I love the DOL and all their free resources. :)
I recently helped a small company revamp job descriptions. The best format or template that I like and recommend is O*net. It gives a nice overview of jobs - including KSAs, work styles, tools and technology, work context and values. It also has a terrific toolkit for businesses. All free.
If you need to update your position descriptions or overhaul completely, this is simply one of the best resources available. Happy Writing.