Leh in the summer is THE Indian destination for the many, many travellers who flood this small town.
It's hard to believe that a shortage of accommodation does not exist in Leh, but from what I saw, there is no shortage.
The guide books mention only a small number of places, which led travellers I met to panic and book into the only places left with rooms - usually the most expensive ones.
I entirely understand that you may want to book in advance, but bear in mind that even in peak season in 2008, there appared to be far more rooms than tourists, and new guest houses are being built constantly.
As long as you've got a decent torch to walk home with, there are beautiful places to stay a short walk away from the centre of Leh, so if you are struggling to book accomodation, I would recommend trying to get a night or two booked somewhere, but then hunt around if you're staying a while - I paid a tiny fraction of the central hotel prices by staying in a family run beautiful but basic guest house 10 minutes walk from the centre.
Of course, you can turn up with no accommodation booked, but it is worth noting that when flying into at altitude, you will give your body the best chance of acclimatisation if you do very little on arrival and rest, rather than hump your bag around searching for the cheapest hotel (which is my tactic in other locations!).
I phoned a guesthouse listed in a trekking book (rather than the more popular mainstream guide books) the day before I flew into Leh, they seemed surprised that I was phoning to book, but I was glad as my flight arrived so early in the morning, I knew there was a room waiting for me, where I could dump my stuff, grab some filtered water, and then cafe-hop for 48 hours of acclimatisation chilling. I was just hugely shocked at how much some other travellers were paying in their upmarket hotels, which they weren't wanting to stay in, but they were all that were available in the popular guide book recommendations.
From the centre of Leh, there are hotels and guesthouses everywhere. The posher hotels tend to be southwest of central Leh, the densest backpacker area is in Changspar (north east). But I think the most interesting accommodation is in the Old Town area (to the east of centre), and off to the west are a few roads that wind through beautifully quiet scenery with homely looking guest houses.
If you've just arrived in Leh, even if you've come by road, for the purposes of allowing your body to acclimatise to the high altitude, beware of walking far with heavy bags.
Is this your business?