Well,
stackoverflow.com is one global site for all
questions, it's not a tool you can install or host.
It's part of stackexchange which is list of Q&A sites.
FYI, I've contacted the guys just to check what is the process to get such a site and
here's their answer:
"
All of our sites are created through a process we call Area 51. It is the staging area to
propose Stack Exchange sites to the community and, if it gains enough support, we create
the site. Stack Exchange sites can only be created via the democratic, community-driven
process at Area 51. You can read more about that process here:
http://area51.stackexchange.com/faq.
"
Thanks
-Vincent
Vincent et all,
did you notice at Area 51 there is a wiki Q&A site proposal in
commitment phase ?
I thought it won't hurt to commit over there although there a quite some
votes missing for that site getting created ...
Might be a bit too general though ...