How to copy a selection to the OS X clipboard

If the clipboard is enabled, you can copy a selected region to the clipboard by hitting "*y

To see if it is enabled, run vim --version and look for +clipboard or -clipboard. For example, it's not enabled by default on my 10.5.6 box:

% which vim
/usr/bin/vim
% vim --version
VIM - Vi IMproved 7.2 (2008 Aug 9, compiled Nov 11 2008 17:20:43)
Included patches: 1-22
Compiled by _www@b77.apple.com
Normal version without GUI.  Features included (+) or not (-):
...
-clientserver -clipboard +cmdline_compl +cmdline_hist +cmdline_info +comments
...

If it had been compiled with +clipboard, I'd be able to use the "* register to access the system clipboard.

I downloaded the 7.2 source and compiled it (easy as tar xjf vim-7.2.tar.bz && cd vim72 && ./configure && make && sudo make install), and the clipboard was enabled:

% which vim
/usr/local/bin/vim
% vim --version
VIM - Vi IMproved 7.2 (2008 Aug 9, compiled Mar 24 2009 17:31:52)
Compiled by rampion@Myrrhy.local
Normal version with GTK2 GUI.  Features included (+) or not (-):
...
+clientserver +clipboard +cmdline_compl +cmdline_hist +cmdline_info +comments
...

However, even after compiling, I couldn't copy to the clipboard when running vim in Terminal.app, only in X11.app.

double-quote asterisk ("*) before any yank command will yank the results into the copy buffer. That works for Windows and Linux too.