[Rise]

Jok3r, можно так:

<style>
.hide_text{display:none}
.show_text{display:block}
</style>

<select name="TOURINC" class="TOURINC" autocomplete="off" onchange="tour(this)">
    <option value="0">----</option>
    <option value="58">ISTANBUL</option>
    <option value="70">BEIJING</option>
    <option value="69">KHARKIV</option>
    <option value="68">LONDON</option>
    <option value="67">ANTALIA</option>
</select>
<div id="info_tours">
    <div id="58" class="hide_text">ISTANBUL - описание бла, бла, бла...</div>
    <div id="70" class="hide_text">BEIJING- описание бла, бла, бла...</div>
    <div id="69" class="hide_text">KHARKIV- описание бла, бла, бла...</div>
    <div id="68" class="hide_text">LONDON- описание бла, бла, бла...</div>
    <div id="67" class="hide_text">ANTALIA- описание бла, бла, бла...</div>
</div>

<script>
function tour(select){
	var info = document.getElementById('info_tours').children;
	for (var i = 0; i < info.length; i++) {
		info[i].className = (select.value == info[i].id) ? 'show_text' : 'hide_text';
	}
}
</script>