I was there in January, after many of the financial problems had rippled through the system. I saw *zero* signs of any problems paying for anything, withdrawing funds from ATMs etc. All services needed by visitors were 100% operational, and the Icelanders were as friendly and kind as ever. The only thing is that when I went to trade dollars for ISK, I was politely advised not to do so and that everyone would happily accept USD and euros. That proved true. Do not exchange currency!!!! Nobody will mind taking your euros or dollars.
When we were there (granted, it was January), there were a number of rooms available all over, at good rates but not spectacularly good... it's not like people are hawking their possessions on highway 1 or something. For most Icelanders, life goes on roughly as before, and the tourist industry is doing fine. Overall, I think you will find that not much has changed. Of course it always makes sense to reserve well ahead. But in terms of overall changes in prices, I don't think you'll see much change at all.
The US issued some sort of travel warning about Iceland while we were there- complete nonsense in my view. I mean, when your currency is weak, you want foreigners to come in and spend foreign currency, duh! So not surprisingly, we were greeted warmly, served well, and made off with some pretty good deals.