Hi M.. We moved to Oak Park about 7 years ago and we have a 6 yo in first grade in the public school here. My younger son is almost three and is in a home-based daycare right now. Oak Park is everything I ever wanted in a community - public transportation, walkable neighborhoods, access to everything, lots of kids and things for them to do, and an involved, warm, intelligent, diverse (economically and racially) community. We're south of the Eisenhower, where housing is a little more affordable but lots and houses are smaller. The people in the neighborhood tend to be an interesting mix of ages and professions although not wealthy - the parents of our kids' school friends are teachers, web designers, scientists, architects, professors, police officers, etc. Further north in town you see more bankers, CEOs, lawyers.
I work (mostly at home) but there are plenty of SAHMs here too - I would guess more than half. You could stop in at Parenthesis (they have a childcare drop-in for parents to socialize, etc.) http://www.parenthesis-info.org/ to meet some mothers. Or stop by the Buzz Cafe (Harrison and Lombard) any weekday morning and strike up a conversation with the owner, Laura, or any of the mothers and kids that come in for coffee and conversation.
Drawbacks of Oak Park are that you pay quite a bit for smaller, older houses and the property taxes are really high. We just had our 3-year assessments, so when you're looking at properties, make sure you get the 2005-2006 information.
There's a visitor's center in downtown Oak Park where you can get all sorts of free maps and information (look for the Answer Book), or check out http://www.oak-park.us/, the village's web site.
Not sure how to answer all of your questions briefly (and I can see this is getting really long!) but I'd be happy to answer more by e-mail -
We are rich in public transportation. (2 L lines, green and blue, plus Metra that runs right through town and just north of here in Galewood.) We also have Pace buses and a free village shuttle bus.
We have dozens of great pre-schools (I'm familiar with many of them) and private schools. We have a beautiful new library with lots of children's programs and great parks and programs (see "property taxes" though :-) We've been very happy with the quality of the public schools so far.