The Jungfrau region is, as far as skiing is concerned, a series of loosely connected resorts in Switzerland, the resort towns being Grindlewald, Wengen and Murren. Also very conveniently located is Lauterbrunnen, and less conveniently, Interlaken, which is where we found ourselves this xmas.
On piste skiing is excellent on all mountains for skiers, but not so good for snow boarders. There's a couple of huge runs (1500-1600m verical drop) that you can do uniteruppted, but they all involve a bit of a cat track at some point, usually at the bottom. Two outstanding runs are from the top of Schilt down to Grindlewald and from Kleine Scheidegg or the top of Mannlichen down to Grund.
Across the three resorts you could easily spend a week just skiing on piste without much repetition, if that's what you're into. If you want to learn or indulge in carving there's a couple of ideal intermediate slopes that are long and wide. Uberjoch and Mannlichen are particularly good for this. There's quite a few black runs, the best being in First (Grindlewald). Black runs are tricky in ice and lots of fun in powder.
As with all ski resorts, when there's a big dump there's a lot of off piste. In the two weeks we were there we had two pretty substantial snow falls. All three mountains offered excellent off piste on a powder day, but the top of the Schilthorn (Murren) was definitely the best for powder longevity. In my opinion there's enough challenging off piste for anyone of any level, assuming you get the snow.
Grindlewald - A large resort town with a mountain railway station. Good access to the 'First' ski area (the principle cable car is in the middle of Grindlewald). Good access to Mannlichen (a gondola to the top of Mannlichen starts on the outskirts) and Kleine Sheidegg (25min train ride from Grund station). Grindlewald is probably a great place to stay in low season, but it's main elevation attractions (Mannlichenbahn and Firstbahn) are a nightmare in peak season.
Wengen - A medium size resort town about a third of the way up a mountain. From here you can get straight on the train to Kleine Scheidegg (20 mins or so) or, depending on where in the town you may be able to get on a chairlift and ski some of the lower areas. There's also a big cable car from Wengen direct to Mannlichen. If you can take the train down to Lauterbrunnen (10mins) you can can then get the Murren Cable car.
Murren - a small and posh ski town with quite a few lifts going straight out of the town up the Schilthorn. Very quiet, somewhat isolated. Very expensive.
Lauterbrunnen - A superbly located town but with no actual skiing of it's own. The train station connects you directly with Interlaken, Wengen and Kleine Scheidegg, you can also get straight up to Murren on the cable car. From Lauterbrunnen you could be skiing in Mannlichen or Kleine Scheidegg in about 30mins. The cable car up to Murren is also pretty quick during off peak times.
Interlaken - A summer resort with train and bus links to the ski resorts. The quickest we managed to get on the slopes was 1hr,5mins. There is a theoretically quicker means. The 9am ski bus takes you in 25mins direct to Firstbahn, the main cable car from Grindlewald up to First. This is fine except for in peak season when the queue for Firstbahn is a disaster (we queued for an hour one day).
There are four ski areas, First (also known as 'Grindlewald First') which is good for intermediates, Murren (slightly more advanced), Murren (excellent for beginners) and Wengen (which we referred to as Kleine Scheidegg to distinguish it from Wengen the town) which has a variety of skiing but is probably the busiest area. Wengen and Mannlichen are just different sides of the same mountain so you could consider them the same ski area.
Getting between ski areas
Other than skiing both Mannlichen and Wengen (which are kind of the same place), it's not really worth skiing more than one area on the same day. In theory you could start really early and ski all of them, but there's no point - you'd waste a couple of hours gaining altitude and sitting on trains and busses.
Switzerland is very expensive, especially for food. Jungfrau is no exception. We saved money by staying in Interlaken but spent a long time getting to the resorts. Lauterbrunnen might be cheaper than the main resorts but probably not by much.
Noteable tourism features
The revolving restaurant at the top of the Schilthorn, which was used in 'On her majesty's secret service' as Blofeld's lair, is definitely the coolest of the attractions. It's no more expensive than other nice restaurants in the area and has one of the best views I've seen anywhere in the world. Go either very early for the 007 breakfast (a 20 quid buffet) or late afternoon and have the daily special (better value). Queueing for cable cars is a bit annoying at other times.
The views from Kleine Scheidegg are spectacular. You can see the North Face of the eiger, and two other larger mountains from pretty much everywhere. You can also ski down the Lauberhorn downhill world cup run and eat at the Bellvue hotel, where Montgommerry once stayed.
Interlaken has some beautiful lake scenery. There's a rip-off train from Kleine Sheidegg to 'the top of Europe' which you could do if you you'd rather do that than go skiing.
Nothing worth mentioning that I saw.