Also, checked here http://www.seamonkey-project.org/dev/nightly for the latest build. Clicked the Windows Installer link and got the following...
Not Found
The requested URL /pub/mozilla.org/seamonkey/nightly/latest-comm-central-trunk/seamonkey-2.1b3pre.en-US.win32.installer.exe was not found on this server.
Apache/2.2.3 (Red Hat) Server at ftp.mozilla.org Port 80