It can work in terminal vim, too.

I believe the special + register for the system clipboard is enabled by a compile option, but that may not be entirely accurate. I have Vim 7.3 installed via Macports and it works for me.

Yes, it's the "+clipboard" option (as shown by :version). If you weren't doing macports (or brew) already, the downloadable MacVIM version does include a "Vim" binary that's usable on the commandline. Somewhere in /Applications/MacVIM.app/... (can't check at work). Just symlinking or simply setting `alias vim='<path_to_binary>` works perfectly.

[MacVim]: http://code.google.com/p/macvim/

I use OSX default vim. That might explain things. I'll try

    brew install macvim --override-system-vim

to see if things improve.

EDIT: it works.

The X11 equivalents are:

    pbcopy = xsel -bi
    pbpaste = xsel -b