Language tutoring with kids

We are looking for a native speaker of English who loves to work with children as a language tutor for our kids (2.5 and 6 yrs). We recently returned from stays abroad in the US and the UK where our kids learned English at school and nursery. We'd like our kids to maintain their English skills so they can stay in touch with their friends. The setting can be very playful and doesn't have to be formal -- a combination with art, music or sports, for example, could work well (or just fun games ;-)).