[melky]

моя версия
Extends : ваый's version;

живой пример :

trArr = $(".table-class tr:not(:first)");
townArr = $("td:nth-child(2n+2)", trArr);


$("#filter-input").keyup(function() {
    if(!this.value)
        return trArr.show()
    trArr.hide();
    townArr.filter(":contains("+this.value+")").parent("tr").show();
});

<input type="text" id="filter-input"  value=""/><br/>
<table class="table-class">
<tr>
    <th>Username</th><th>Adress</th><th>Acess</th>
</tr>
<tr>
    <td>Вася</td><td>Москва</td><td>Read</td>
</tr>
<tr>
   <td>Лёша</td><td>Питер</td><td>Write</td>
</tr>
</table>

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js"></script>
<script>
trArr = $(".table-class tr:not(:first)");
townArr = $("td:nth-child(2n+2)", trArr);


$("#filter-input").keyup(function() {
    if(!this.value)
        return trArr.show()
    trArr.hide();
    townArr.filter(":contains("+this.value+")").parent("tr").show();
});
</script>