Thanks for the lunch offer, Iggy - sadly, I think we're likely to be moving back to the UK in July as dh's work is finishing ahead of schedule. What line of work is your DH in? All the Irish people I know seem to work for Ericcson, the phone people, though I'm sure that's just a coincident!
Re schools, if you're living in Kemang then it is quite a long haul to BIS, probably 3/4 or an hour but lots of people do it and from much further away. Transport is proved (for a price!) but some people prefer not to use it because of the possiblity of buses, as well as schools, being a terrorist target. My dh's company wouldn't pay for transport so I take dd by car every day. I wouldn't be too worried about getting places at pre-school. Expats come and go so much that there are always vacancies coming up. Jis is about 30 mins away from Kemang. AIS isn't well regarded and there have been rumours that it is to shut down. If you look on the expat website, it has lots of info on the various schools. There's a new book just out that you'll want to buy, called "Jakarta for Under Fives.' It is a great publication and useful for all expats, not just those with children, as it is stuffed with info.
You will need to get used to spending a lot of time in the car, wherever you live. No one walks anywhere much, as it's too hot and also Jakarta is a very spread out city without a specific centre. Kemang is the expat ghetto so it is more Westernised than the rest of the city, with prices to match. Weekend/holiday traffic in Kemang is terrible, we've given up going there on those days. It can take up to 1.5hrs to go a mile! There are very few major accidents in town as you mostly move along at 3mph!! The toll/ring roads are a different story. Make sure your car has rear seatbelts. They are not standard issue but we had them fitted throughout. The car of choice is a Toyota Kijang, a sort of 7/8 seater offroader type vehicle, built to withstand the rigours of the road surfaces. There haven't been any riots since we came here. Indonesians are very fond of demo's but they are tightly organised by the Polisi and take place near the govt biuldings and CBD, and you shouldn't be affected except for the traffic chaos that ensues citywide.
I'd really recommend joining The British Women's and the Australian and New Zealand associations (BWA and ANZA) as they open up a whole new side of life out here. As well as providing support to expats they give you a chance to put something back into Indonesian society, through their various charity works. It'a also a small world out here - I recently met someone who knows our plumber back in the UK!!! The Indonesian Heritage Society is great for getting to know about Indonesia and they have a lovely library with books on the subject. Which reminds me, books are readily available here but there's less of a choice and they are expensive. Bring as many books for your children as you can, including ones currently too old for them, unless you will be able to stock up from home regularly.
Finally, you don't want to employ a fanastic cook/housekeeper, do you?? She's wonderful, a real gem.
Anyway, must go now and brave the roads!! HTH