XPages let’s you choose field level help, but personally I like my approach and it works in any traditional form or xpage. It lets me control in a central form all help and still grab only what I need when I need it. Since I use Hide/whens the server gives me only what I want too. It is pulled via an AJAX call, bundled into a JS Library.
Choose the Field Level Help Example option.
Enjoy!
-TIM