I've been waiting years for this to be made/become available. It has apparently been available in the UK for some time which is not surprising because not only is a young David Tennant in it, he apparently also narrates the commentary which is an extra on the DVD.
I don't know about other places, but JB Hi Fi is listing it as being available from 5th February, 2009. I've already ordered a copy.
A lot of David Tennant fans have bought it simply because he is in it. Take my word for it that it is worth seeing even if David wasn't in it - i.e. the other actors are also excellent and it is well written and directed IMO.