eregi alternatives

I'm going to use a lot of searches for occurences of words in a long text:
$string = "a 500 character Text";
if (eregi("text", $string)) { print "found";}

Eregi should be very slow, so I'm looking for alternatives. Any suggestions?
I guess I could use something like
$string = strtolower($string);
if ( strpos($string, "text") !== false ) { print "found";}

Is that the best solution?







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