I found this trick from this web.
The idea is by wrapping facebook code with your own customized DIV, such as:
<div id=”likeboxwrap” style=”width: 298px; height: 393px; background: #FFFFCC; border: 1px dashed #FF3300; overflow: hidden;”>
put fb code here
</div>
or anything alike..
<div id=”likeboxwrap” style=”background: white; border: 1px solid black; overflow: hidden;”>
put fb code here
</div>