http://cvs.debian.org/srcdep/Packages-arch-specific?root=dak&view=markup

This information is already listed in Jeroen's buildd status[1], but I
think it would be a good idea to have it on the PTS page as well, as
quite few maintainers seem to be aware that their package is in P-A-S.

[1] http://buildd.debian.org/~jeroen/status/package.php?p=scheme48