I've made several batches so far. I much prefer the stovetop method to the oven method....but to each his own. Since it's already been so well covered by other bloggers I thought I'd just point you to their resources rather than re-make the ghee wheel.
From The Nourishing Gourmet
From the Healthy Home Economist...with video
this is the explanation I refer to most often
Thus far I have only used Kerrygold unsalted butter, because that's what I have available to me, and it's one of the best. We go through this much more quickly than I thought we would so I end up making it often!