(PHP3 >= 3.0.6, PHP4 )
stristr -- 
     Case-insensitive 
strstr()
    Description
string stristr (string haystack, string needle)
     Returns all of haystack from the first
     occurrence of needle to the end.
     needle and haystack
     are examined in a case-insensitive manner.
    
     If needle is not found, returns false.
    
     If needle is not a string, it is converted
     to an integer and applied as the ordinal value of a character.
    
     See also strchr(),
     strrchr(), substr(), and
     ereg().