first explode the string on every ;, next explode every array element on :
http://de.php.net/manual/en/function.explode.php
e.g.:
$tmp = 'description title:description text;description title2:description text2';
$tmp2 = explode(';',$tmp);
returns:
$tmp2[0] = 'description title:description text';
$tmp2[1] = 'description title2:description text2';
now you could do something like:
$tmp3 = array();
foreach($tmp2 AS $value){
$tmp3[] = explode(':',$value);
}
and you get
$tmp3[0] = array(
0 => 'description title',
1 => 'description text'
);
$tmp3[1] = array(
0 => 'description title2',
1 => 'description text2'
);