From the Hail Bob64! dept.:
Ready or not, Slackware has now gone 64-bit with an official x86_64 port being maintained in-sync with the regular x86 -current branch. DVDs will be available for purchase from the Slackware store when Slackware 13.0 is released. Many thanks go out to the Slackware team for their help with this branch and a special thank you to Eric Hameleers who did the real heavy lifting re-compiling everything for this architecture, testing, re-testing, and staying in-sync with -current.

slackware.com

wikipedia.org Bob Ref.