> Does anyone know if there is genealogical software
> designed specifically for Icelandic genealogies

Yes, there is. This is what my grandfather uses:
http://www.frisk.is/espolin.html
I doubt it would suit you well, though. It runs
under MS-DOS and the interface is somewhat arcane.
I think it's also rather expensive.

There's also Íslendingabók: http://www.islendingabok.is/
which is much more user-friendly. While it doesn't
allow you to enter information on your own I think
it already contains the genealogies of the sagas.

Access is free but from the site it seems you have to
have an Icelandic 'kennitala' to get a username. Maybe
you could write them and ask for one anyway.

Kveðja,
Haukur