[bushstas]

<style>
  .style1 {color:#FF0000;}
  .style2 {color:#000;}
  .style3 {color:#FFF;}
</style>

<a href="blabla"  class="style1" onmouseover="changeStyle(this,'style2')"  onmouseout="changeStyleBack(this)">Ссылка</a>

function changeStyle(obj,c){
curClass=obj.className
obj.className=c
}
function changeStyleBack(obj){
obj.className=curClass
}