Regarding your question about pop-up windows, the simplest (but not the prettiest) way is to use a link tag like:
And put your tip in "pop-up.php". When the user clicks on the link, a new window is opened on top of the old window. A better way might be:
though I don't know if that will work on all browsers. Third way:
Substitute the sizes in pixels for height and width ###'s. Careful with the single and double quotes. And window.open MAY need to be changed to window.concat instead. And finally, a very complex way, that I'm not sure I've gotten right, but if I did, it has the potential to be the nicest:
You'll need to adjust the position and width stuff (and will probably want to alter the color and font stuff as well).