[Pythonmac-SIG] Can someone help me reverse engineer this installer?

[skip at pobox.com]

A long time ago Sam Thorne created a Mac installer for SpamBayes.  It's
referenced here:

    http://entrian.com/sbwiki/MacOSXPackage

and source is available here:

    http://www.s-j-t.co.uk/SpamBayes/SpamBayesPkg%200.5.zip

The binary package here:

    http://www.s-j-t.co.uk/SpamBayes/SpamBayesPackage.pkg.tgz

won't untar for me.  It complains about a "lone zero block at 678".

I'd like to start generating Mac installer packages for the normal SpamBayes
distribution, but for that I need some help getting started (having never
done any Mac package creation before).  I sent email to the author asking
about how he created the one he did but haven't heard back from him (maybe
he's just on holiday).

Can one of the MacPython experts here deduce how the above package was
generated and suggest how to proceed?  I don't even know what the best
package creator is on the Mac for Python-based apps.

Thx,

Skip Montanaro