I’m using bootstrap 2.0 to make a fluid layout. However, I find it break bad when the browser is resize or when I see it from a iPhone:

This is my markup:
<div id="features" class="row-fluid">
<div class="span12">
<ul class="thumbnails">
<li class="span4">
<div class="thumbnail">
<img src="http://placehold.it/128x128" width="128" height="128" alt="Orders" />
<h3>Pedidos</h3>
<p>Genera ordenes de pedidos para su facturacion posterior</p>
</div>
</li>
<li class="span4">
<div class="thumbnail">
<img src="http://placehold.it/128x128" width="128" height="128" alt="Invoices" />
<h3>Facturas</h3>
<p>Factura las ventas realizadas</p>
</div>
</li>
<li class="span4">
<div class="thumbnail">
<img src="http://placehold.it/128x128" width="128" height="128" alt="Customers" />
<h3>Clientes</h3>
<p>Ingrese & actuelize los datos de los clientes</p>
</div>
</li>
<li class="span4">
<div class="thumbnail">
<img src="http://placehold.it/128x128" width="128" height="128" alt="Products & Stock" />
<h3>Productos</h3>
<p>Ingrese & actuelize los datos de los productos y su inventario</p>
</div>
</li>
<li class="span4">
<div class="thumbnail">
<img src="http://placehold.it/128x128" width="128" height="128" alt="Sincronization with ERP" />
<h3>Impresion</h3>
<p>Genera impresion de tiquets en papel con la impresora P25</p>
</div>
</li>
<li class="span4">
<div class="thumbnail">
<img src="http://placehold.it/128x128" width="128" height="128" alt="Sincronization with ERP" />
<h3>Sincronizacion</h3>
<p>Sincroniza los datos con ERPs seleccionados</p>
</div>
</li>
</ul>
</div><!--/span-->
</div><!--/row-->
(The same markup with zero CSS aplied break bad too)
I have tried by CSS to put a width/height but that break the flow.
Bootstrap now have responsive support, and the 3.0 Branch will have it by default.