Mouse over text, image appears

Hello!
I've been searching for something for quite a long time now, but I haven't found anything... could you help me please?
How can I get an image to appear when the mouse moves over a link? You just move the mouse over it and the image appears next to the mouse, or anywhere else on the page.
Ideas, anyone? Would be glad :)
Greets, snowangel.

See this.

Thanks for this fast reply!!
Is this like on this page? www.ednetz.de
Move the mouse over a bold nickname, and a photo appears...
Can I also do this with text? I mean, like a biography which appears next to the name.