There's probably a simpler way, but this will work:

$count = "0"
while (/(.)/g) { 
        $count++
}
print $count
[download]

- Ozymandias

Update: That's what I get for posting nodes after my bedtime. <G> Yes, I knew about "length", but btrott had already posted an answer using that; I decided to see if there was another way. Why? Because. And that's all the explanation I'm going to offer. <G>