Security :: IPTables And SSH Rate Limiting

I'd like to discourage the SSH bots that try to log into my system (CentOSv5), and among other things, I've changed my SSH port to someting other than 22. As well, I've been playing around with the idea of some iptables rules (note port 22 is used here as example):
Code:
# Allow SSH with a rate limit
iptables -A INPUT -i ppp0 -p tcp --syn --dport 22 -m hashlimit --hashlimit 15/hour --hashlimit-burst 3 --hashlimit-htable-expire 600000 --hashlimit-mode srcip --hashlimit-name ssh -j ACCEPT
iptables -A INPUT -i ppp0 -p tcp --syn --dport 22 -j LOG --log-prefix "[DROPPED SSH]: "
iptables -A INPUT -i ppp0 -p tcp --syn --dport 22 -j DROP
I am *NOT* an iptables expert. What do you all think about the above code snip?