{foreach array('a','b') as $key => $value}
{$key." : ".$value}
{/foreach}

{var $array = array('a','b')}
{foreach $array as $key => $value} 
{$key." : ".$value}
{/foreach}

{foreach 'a'..'b' as $key => $value}
{$key." : ".$value}
{/foreach}

{foreach array_fill_range('a','b') as $key => $value}
{$key." : ".$value}
{/foreach}