Montessori programs can be good (though keep in mind there is a ton of variability in Montessori programs) as they can have mixed age groups (3-5 or or 3-6 or something like that) so a gifted 3 year old could run around with NT 3 year olds and talk to the 5-6 year olds.
We consulted with a psychologist on the hoagies list:
http://www.hoagiesgifted.org/psychologists.htmWhile this was not cheap, he saved us a ton of time by recommending programs that were appropriate (and also doing some IQ testing to establish probable giftedness).
Keep in mind that public or private school is only part year and part day, so when kids age out of traditional year-round full day childcare there are some pretty big gaps (summer and other vacations) that need to be filled.
