You can use the modulus operator to determine if your loop variable ($j) is currently odd or even, and then apply a CSS class as appropriate. In one line, you could change your opening li tag to something like this:
<li class="<? ($j % 2) ? echo "even" : echo "odd"; ?>">
CSS could be applied like this:
.newsfeed li.even{ background: #fff; }
.newsfeed li.odd{ background: #efefef; }
Chris
2009-11-08 20:34:40