Last year, we were looking to go on vacation, but didn't know the best way to go about it. A hotel would be too expensive and we didn't want to camp with Dan being so little (about 6 months old). Friends told us about this website called HomeAway, where you can rent anything from a little studio apartment to a large multi-family chalet. We tried this place in West Virginia and had a great time. Great little house, a little off the beaten path, which was fine with us. We were able to pay for the rental by paypal and the owners were very helpful both before and after our stay.
So, having had such a good experience the first time, we went through HomeAway again for this year's vacation. This year,we stayed here. The funny part was realizing that the owners live in Newcastle. As it happens, Scousers have great taste in holiday homes, because this was another great place - plenty big enough for us and having everything we needed. Unfortunately, we had to leave early due to Eleanor coming down with some sort of tummy bug - we didn't want to risk the rest of us getting it and having to cope with an 8-hour drive at the same time!
The HomeAway website is very well set up. Plug in some of the features you'd like (bed, bath, etc), the area you'd like to go to, and the price you'd like to spend - then you can start shopping! It's got reviews, which are very helpful, mapped locations, and all sorts of other helpful details that can help you make your choice.
I think 2 years of good experiences warrants a recommendation, so if you're looking for holiday options, HomeAway is worth a look.