Thanks very much, you were all quite right, the first iteration found no value ( uninitialised! doh! ) so i made it increment from 0 before i did stuff on it.. now it works fine... thanks perl monks!

$alphabet{$s}++;
    open (DATA, ">> ./ATOZ/$s.shtml" )or die "can't open file: $s!";
        if (($alphabet{$s}) % 2){
            print DATA qq|<tr bgcolor="#eeeeee">;
        } else {
            print DATA qq|<tr bgcolor="#FFFFFF">|;
        }
    close DATA;
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