We stayed in a place right behind the church/cathedral in the main square called Hotel de Emauspoort. It was very nice, and the service was good.
Website is here - [broken link removed]
B&B Oosteinde replied late to our enquiries, but sounded like it would have been very nice. They had just had a kid back in January, so I guess families are welcome. Their website is - www.nlweb.nl/hotels/delft...einde/ned/
Didn't see much of Delft - it was raining and we were only there for a day.
We ate at an eetcafe called 'de Ruif' just across the road from the Emauspoort. Well worth a visit, but don't let your kids drink too much milk and then throw up down the spiral staircase . . . they won't appreciate it and may ban *all* Irish people.