No online sites that I use to meet other families--we are fortunate to live in a very multicultural area and the majority of other families we know (thought dd's pre-school class) are actually bilingual familes.
Also, you know there have been a number of good books written about this. A quick search on Amazon should bring several resources up. A decent "starter" book is "Raising Bilingual Children: Parent's Guide"
by Carey Myles.
But here, check this link:http://www.amazon.com/s/ref=nb_ss_gw...+bili&x=9&y=22
Granted, reading books may not be the same as talking with other families, but many have case studies and interviews with multilingual families and you might actually find reading about families in similar positions and struggling with similar issues to be a source of some kind of support.