Basically I need to open a login window in a popup, so that it doesn't get blocked by popup blocker. Similar to what Janrain does in it's RPXnow solution. How do they do that?
Most pop-up blockers allow pop-ups that were triggered by a user action, e.g. clicking on one of the login links on the page you linked to.
So if you tie your login popup to a login button that the user has to click to open it then it ought to get past the blockers OK.
(or am I missing the point - were there other examples of popups you meant other than on their home page?)