<p id="a">ЗДЕСЬ ПИШЕМ ТЕКСТ</p>  
<script language="JavaScript" type="text/javascript">  
function change()  
{  
re="rgb("+Math.round(Math.random()*256)+","+Math.round(Math.random()*256)+","+Math.round(Math.random()*256)+")"  
a.style.color= re;  
}  
setInterval(change,1000);  
</script>