The documentation  for this is pretty awful, but there are some examples in
the MS SDK & in www.sharepointcode.com . You can access  SPS from ASP or from
VB (com or exe) quite easily, although I think your implementation must have
SPS and whatever external  app. you are running [which will use the SPS
object module] on the same machine/box. We have tried running on separate
boxes and it just won't work - we keep getting 'access denied' errors. Prior
to this, we managed to probe all the security settings, check out docs, etc.
when the two were on the same box. I could be wrong about this last issue in
which case please let me know!