Avoid cross-browser javascript when you can use css to make tooltips with less code. Honestly you were going to use css to style your tooltips anyway right? Your probably already have most of this code in your css already too. Besides that if you have an advanced site in the first place you probably have enought javascript already.

Also with the IE hack for the :hover state, you can do this with elements besides anchors.

If you dont like how it allows you to hover over the tooltip also then you can adjust the padding and top to separate the tool tip from the link.

View Full Example and Code

Download Source