There a few of ways to do this…the first is probably the best method. The second one is a css trick/hack and should really only be used when a hack is absolutely necessary.
1)
/" title="" rel="home">; ?/>/images/logo.jpg)
2)
a.logo{
background: url(logo.jpg) no-repeat left top;
text-indent: -9999px;
}
/" title="">