conditional preg match

Hello,

The following bit of code does a preg match and does something if true (sets $browser to ppcie)

Without using if then and else's how do I code it so it does not equal what it is testing for? So if it does not find ppc in the $agent then it does something else/sets it to something else?

$agent = getenv("HTTP_USER_AGENT");
if (preg_match("/PPC/i", "$agent"))  {
	$browser = 'PPCIE';
	}

Thanks,

td.
www.pocketpcheaven.com
.