Showing Category Name in the url with .htaccess

Hi, I have a script that use .htaccess url rewrite in order to show bettter url.
It is a classified ads script. In the home page, you have a list of category. Their url looks like:

http://www.mysite.com/categorie/2

where 2 is the Category ID.

Now, I would like this url to become:

http://www.mysite.com/cars/2

with the category name istead of the word "categorie", if I click on the cars link (of course!).


This is the actual rewrite rule:
RewriteRule ^categorie/([0-9]+)$ ads.php?c=$1 [L]

This is the php code in the page that prints out the categories list:

$q1 = "select * from class_categories order by CategoryName";
$r1 = mysql_query($q1) or die(mysql_error());

while($a1 = mysql_fetch_array($r1))
{
      $MyID[] = $a1['CategoryID'];
      $MyName[] = $a1['CategoryName'];

      $q2 = "select count(*) from class_catalog where CategoryID = '".$a1['CategoryID']."'";
      $r2 = mysql_query($q2) or die(mysql_error());
      $a2 = mysql_fetch_array($r2);

      $MyNumber[] = $a2[0];
}


if(!empty($MyID))
{
      for($i = '0'; $i <= (count($MyID)); $i+=2)
      {
            $one = $i;
            $two = $i + 1;


            $categories .= "<tr>\n\t\t";
      
            if(!empty($MyID[$one]))
            {
                  $categories .= "<td width=\"265\"><a href=\"categorie/$MyID[$one]\" title=\"Ads $MyName[$one]\" class=\"BlueLinka\">$MyName[$one]</a></td>\n\t\t";
            }
            else
            {
                  $categories .= "<td width=\"265\">&nbsp;</td>\n\t\t";
            }

            if(!empty($MyID[$two]))
            {
                  $categories .= "<td width=\"265\"><a href=\"categorie/$MyID[$two]\" title=\"Ads $MyName[$two]\" class=\"BlueLinka\">$MyName[$two]</a></td>\n\t\t</tr>\n\t\t";
            }
            else
            {
                  $categories .= "<td width=\"265\">&nbsp;</td>\n\t\t</tr>\n\t\t";
            }

}
}


Does anybody help me?