The latest verion of sudo is 1.6.3p7
The "authoratative" sudo ftp site is ftp://ftp.courtesan.com/pub/sudo/
and there is a web page at http://www.courtesan.com/sudo/

Note that these archives are now compressed with gzip, if you
don't have a copy of gzip, download gzip-1.2.4a.shar from the
"misc" subdirectory.  To unpack an archive, do:
    gunzip -c sudo-1.6.3p7.tar.gz | tar vxf -