I'd prefer something more readable than concise. It's a concise enough problem anyway.

sub b26_to_b10 { 
    my $base_10 = 0; 
    for (split //, lc shift) { 
        $base_10 *= 26;
        $base_10 += ord() - 96; 
    }
    return $base_10;
}
[download]

-sauoq
"My two cents aren't worth a dime.";