Is it possible to mirror the db in Postgres?

We use Postgres 7.0.3 to store data for our scientific research. We have
two other labs in St. Louis, MO and Tempe, AZ. I'd like to see if
there's a way for them to mirror our database. They would be able to
update our database when they received new results and we would be able
to update theirs. So, in effect, we'd have 3 copies of the same db. Each
copy would be able to update the other.

Any thoughts on if this is possible?

Thanks.
-Tony Reina