In the past me and the missus have used professional pet sitters and friends.
The professional pet sitters are great. Depending on what you pay for, they come once or twice a day, feed and water the pets, and take them on walks. We have two dogs and usually go with a once a day visit to feed and water. That usually costs $15/day and we always tip at least 20% of the bill at the end. The one downside to professional petsitters is that they do not stay at the house.
Friends usually can also house sit as well as take care of the pets. That means getting the mail, watering the plants/lawn, and also feeding and watering the pets and taking them for a walk. For six nights, we usually pay them between $50 to $75 and make sure the fridge is stocked with their favorite beverage. They also have access to the kitchen as well as access to our well stocked library of Disney DVD's and videos.