I got two resources from a colleague - an amazing web designer (I was shocked by some UI things he have done in some projects and in our home page http://www.ssw.com.au)
1. Tooltips with AJAX, JavaScript and CSS http://www.smashingmagazine.com/2007/06/12/tooltips-scripts-ajax-javascript-css-dhtml/
2. Tips for CSS
http://www.smashingmagazine.com/2007/05/10/70-expert-ideas-for-better-css-coding/
I never knew that CSS can do work like making text in upper case or in lower case...
h1 {
text-transform: uppercase;
}
h1 {
font-variant: small-caps;
}
[Update]: another handy firefox add-on for UI debugging -
http://www.getfirebug.com/