Data cell light up effect on mouse rollover

Hi,

Do any of you guys know what language I need to use to make each content cell change colour when a mouse rollovers it?

For this site, http://individual.utoronto.ca/ckcj/fmm/fmm.htm notice how there’s content under each header? How would I make the background colour change when I rollover the text with my mouse cursor?

Thanks in advance.