If you put Istanbul into the Search facility and choose Topic Titles you should find 2 reviews by ellie_meg with info.

luci

we took our daughter last oct half term to istanbul for a week she was 8 and had her 9th birthday there. there was plenty to do she enjoyed and some things she didnt enjoy, mainly the mosque's she found boring, she loved her birthday trip to the princes's islands, so you should fill 3-4 days easily, but we did have some rainy days aswell as sunny days so be prepared, also the istanbul marathon was on so 1 day it was very busy outside the blue mosque area. either read my reviews ,any questions ill be happy to help if i can

karen

i argee with elliemeg for three days you will only be scratching the surface there is so much to do but if your children are not into culture the sites are wicked and of course there is taxim square ( regents street turkish style )

I'm sure the kids will enjoy "Miniaturk" and the "Koc Museum"

http://www.miniaturk.com.tr/default.asp?git=99&id=50

It is on the shores of Golden Horn and is a great place where your child can run around, see al the small models of Istanbul and Turkish sites and it would be interesting for you as well. It is very child friendly.

http://www.rmk-museum.org.tr/english/index.html

Nearby there is also an industrial history museum, Rahmi Koc Museum, again on the shore of Golden Horn a short distance from miniaturk. There are submarines, old cars, planes, models and toys and many wonderful displays.

might be worth to check out the Istanbul Toy Museum and it is a small museum dedicated to toys. The museum is located in the Göztepe district .

http://www.istanbuloyuncakmuzesi.com/eng/kurumsal.asp

http://www.allaboutturkey.com/ist_muze.htm

Bahcesehir College Science Museum

One of the newest museums of Istanbul opened in June 2008 inside the Bahcesehir private highschool. The museum has several tools and work stations aiming young children to explore the scientific world. Young visitors can test and learn several facts of science and physics at the interactive stations and research labs. There is also a Planetarium, sky observation station, and a 3-D movie theater for scientific educational films.

Open daily between 10:00-16:00 except weekends.