PHP

<?php if( $count=$this->countModules('user') ) {
if ($count==1) { ?>
    <div class="user style960">
    <jdoc:include type="modules" name="user" style="xhtml" />
    </div>
<?php  } ?>
<?php if ($count==2) { ?>
    <div class="user style480">
    <jdoc:include type="modules" name="user" style="xhtml" />
    </div>
<?php  } ?>
<?php if ($count==3) { ?>
    <div class="user style320">
    <jdoc:include type="modules" name="user" style="xhtml" />
    </div>
<?php  }
  } ?>

CSS

.user .moduletable {
display: inline-block;
}
.style960 .moduletable {width:100%;}
.style480 .moduletable {width:49%;}
.style320 .moduletable {width:33%;}