Unfortunately wine isn’t quite ready for the 64 bit world of Snow Leopard, and the default port of wine in MacPorts won’t install at all (it says: please wait for Wine 1.2). Worse, installing wine-devel (the bleeding-edge alternative) crashes with obscure error messages.
Here’s the trick:
sudo port install wine-devel sudo port upgrade --enforce-variants \ expat fontconfig freetype jpeg libiconv \ libxml2 libxslt ncurses openssl zlib \ mesa +universal sudo port install wine-devel
(Of course, this assumes you’ve reinstalled MacPorts. It’s just not a good idea to try to upgrade your installation from before Snow Leopard. Read this.)