Personally I believe that any attempt to link these two families has to be
prefaced with a very, very tentative "maybe". There are even attempts to
link this putative combination with Sino-Tibetan; well, anything is
possible, I suppose.
Until this thread came along, I was unaware that _anyone_ was willing to
include Austronesian within Nostratic. Nor is it included, AFAIK, in
"Proto-World", which seems odd.....:-)
In December, there was some interesting discussion of the question on the
Yahoogroups Austronesian list--
http://groups.yahoo.com/group/austronesian (messages in Dec 02, mostly,
about #400 et seq; you may have to enroll to read the archive, but that's a
simple matter)-- look for those by Laurent Sagart and L.V. Hayes (they seem
to be qualified scholars, even if they seem to not have a very high opinion
of each other....). These will give you a fair idea of some of the problems
involved, and the occasionally suspect stretching of phonological/semantic
possibilities.
Others have correctly pointed out where Austronesian languages are spoken;
for total accuracy let's include Madagascar, and a number of languages
spoken along the north coast of Papua-NG to down around the SE corner.
The so-called Indo-Pacific group seems more a cover term for a mixed bag of
languages, rather than an actually _proven_ family, and includes some relic
groups within Indonesian territory, plus all the non-AN languages of PNG and
nearby islands. Whether it also includes languages of Australia, I do not
know.