Sunsail holidays. They are fab. They have kids clubs starting from 3 months of age with fully qualified nannies. Special meal times and food for kids - no junk, no salt, just proper kid friendly food. Baby listening services for the evenings. Night creches for evenings you want to go out off the resort. All inclusive with lots of activities if you're not a sailing fan and it's fabulous if you do like sailing.
Unlike other kids clubs you don't have to check them out at lunchtime, they feed them lunch. So you can take a yacht out (fully inclusive in price) and spend the whole day sailing around islands and come back in time to pick them up for supper.
They usually have kiddy pools depending on which resort you go to and the kids have a ball. I think the clubs go from 3months to 2 (and they keep the bigger kids away from the babies), then 2 to 4, 5 to 7, 7 to 11 and teens. I could have that a bit wrong but that's the basics. They all get given little matching t-shirts, caps, cups and bags and they spend all day marching about, singing songs, playing marco polo in the pool etc.
The adults get to have yummy meals and you meet loads of other parents who're all in the same boat. They also all have spas for relaxing treatments.
I cannot praise it enough. The only warning I would have is not to go to Club Perilli in Turkey if you have very little kids as there is a 3 hour transfer from the airport to the hotel and it's on bumpy roads. After a 4 hour flight - it just makes the trip too long. But they have lots of resorts with far shorter transfers.
www.sunsail.com
Hope that helps