out-of-business registrar

[mmccaws2]

we have a client who's domain registrar has gone out of business.
i-theta.com was the registrar.  Does anyone know what happens to
abandoned domains, as in are they acquired by other registrars.  If so,
how do I go about finding who has acquired the domain.  Or does my
customer just find another registrar? The domain in question is
ci.woodinville.wa.us.

Thanks

Mike