Took a while to work this command out. Hopefully it can save someone else some time.

sudo port install mysql5-server
sudo env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-config=/opt/local/bin/mysql_config5
written by
Disagree? Found a typo? Got a question?
If you'd like to have a conversation about this post, email I don't bite.
You can verify that I've written this post by following the verification instructions:
curl -LO
curl -LO
gpg --verify installing-the-mysql-gem-on-osx-106-snow-leopard-with-macports-mysql5.html.orig{.asc,}