xml remove <br /> tag

Hello,

I try to read a xml file with this schema:

- <item>
<title>some text</title>
<link>link</link>
- <description>
text ok
<br />
I can't see this text </description>
<imedia:thumbURL>link</imedia:thumbURL>
</item>

When I write:
echo $rss_channel["ITEMS"][$i]["DESCRIPTION"];
I can see text ok, but from <br /> I can't see nothing.

I tried to use somethink like eregi_replace("<br />", "\n", $var); but with no effect. Could you help me ?

And for <imedia:thumbURL> what channel shoud I use ?

$rss_channel["ITEMS"][$i]["imedia:thumbURL"]; or $rss_channel["ITEMS"][$i]["thumbURL"]; are not working.

Thank you!