I've used
http://www.barkingmad.uk.com/a few times, very successfully. They have host families so the dogs go and stay in their home. I've also taken dogs in, in the past, as a Barking Mad host. I've found it has worked very well. Slightly more expensive than kennels but something I've been happier about. Not used anyone to house sit my dogs ... god, the cleaning beforehand!! But there are a number of organisations, I think Animal Aunts is one, but never used so can't recommend.
Might be worth checking at your vet if anyone has recommendations if going the house/dog sitter route.