Installed Modals & followed example to create Menu Item with {modal}Login{/modal}
Seemed to work perfectly BUT on hitting login the Modal window stayed but contained website Homepage.
Also If I close this modal window the original webpage has not been refreshed - still shows user not logged in.
For that to work, you would need to make the login form post to the parent (so not just the iframe).
Or place the login form inline, but is a bit more work to get working.