PHP Condition for ie

<?php if(preg_match('/(?i)msie [1-8]/',$_SERVER['HTTP_USER_AGENT']))
{
    // if IE<=8
    include ( TEMPLATEPATH . '/noie.php' );
    exit;
}
else
{
    // if IE>8
} ?>

Create new theme

Website/catalog/view/theme

Copy default theme and make a new theme using copied theme

Implementation:

SystemàSettingsàStore->Template __ selects our theme