Changing a power steering pump on a 99 Windstar

I need a new power steering pump in my 99 Windstar (3.8). I've done some minor maintenance on the vehicle myself, such as replacing hoses, the serpentine belt, and, recently, the alternator. I'm trying to decide whether or not to attempt to replace the steering pump myself or have a real mechanic do it. Web searches are inconclusive -- some say it's easy, others say don't try it. Any thoughts?