Just about everyone with a tripod, long lens and a camera has tried to take a shot of the moon at some point as it's such an obvious subject and just about always there. And that includes me too =). In fact, it isn't very difficult, but there are some gotchas that you do need to bear in mind.
1) Use a tripod, remote release and a couple of seconds delay. That way you ensure that your camera is stable. And if you have a big lens mounted you'd be surprised by how much it wobbles after you've adjusted it for focus... hence the delay.
2) This uses a Sigma 150-500mm at the 500mm end. It was a revelation how nice and sharp it came out, as at the 500mm end this lens isn't the sharpest.
3) During the day contrast can be a problem, so take the shot whilst the moon isn't a full moon. Full moon means light is coming straight at it, so no shadows and little contrast. In this pic above the light is at a bit of an angle which adds shadows so you see some nice craters etc.
4) Exposure - for this I used 1/160 and f8 - the moon is surprisingly bright.
5) Cool freebie - image stacking software. There are various of these available but the one I've personally found easiest to use is Registax. So what they do is stack images (in this case 5 at the same exposure) to draw out details that you might not see in just the one image. That's how the pros do it so worth doing. Google "registax" - or download it from registax.astronomy.net/
6) White balance - in this case I used 'cloudy' but it's probably wrong =). Looks to me that the blue is a tad dark (hence noisy), but heyho I can live with it.
7) Focus - I focused manually for this. Quite tricky to do actually because the detail through the viewfinder is so dang small. But be aware that taking your zoom and cranking it out to the farthest possibly focus absolutely won't work, because zooms tend to have their farthest focus set at beyond infinity. (Common trap to fall into).
8) Sharpening - it's so terribly easy to overdo it. This has none whatsoever, just noise removal using a photoshop plugin called "noise ninja" (about $100).
9) Locking focus - I used pieces of electrical insulation tape to lock both focus and zoom. On the Sigma 150-500mm, the weight of the thing and the angle that I was pointing meant that the zoom moves all by itself... so electrical tape is your friend.
10) Needless to say, I shot in raw to allow myself some flexibility in post editing.
11) ISO - use the lowest on your camera
12) Shoot when the moon is as high as possible in the sky rather than low. If it's low in the sky you're trying to cut through a lot of atmosphere, which makes for haze on the photo.
13) Obviously, use a clear night - any hint of cloud and you'll lose detail.
14) I didn't use an equatorial mount (thing that rotates as the earth rotates), a telescope, a specially adapted camera, a teleconverter or any filters. You honestly don't need these to do the moon. For space astrophotography, yes, but the moon, no. The moon is perfectly accessible without all this specialist equipment =).
15) #4 is open to debate, and some people vastly more knowledgable than me consider this unneccessary. The way stacking works is by increasing the signal:noise ratio so for a simple moon shot (considered daylight) there isn't the need. That said, it helped find details on this so perhaps it doesn't do any harm either.
/16) Update to #15, it turns out that registax stacking is a form of super resolution - link to wiki article explaining it better than I ever could.
If you're interested in startrails you should have a look at this photo, which explains how to do these. Tagged with "supermoon" to help supermoon shooters this weekend - good luck =)