Finally ported to Win32. It was actually a simple matter of changing how command pipes are created.
Added 'smtp' option to enable sending messages to an SMTP server rather than to the local 'sendmail' application. This is essential for Windows support.
Added --io-layer to the usage statement in 'svnnotify'.
Fixed single-dash arguments in documentaion so that they're all documented with a single dash in SVN::Notify.