I guess I should document this since I spent some time to get this to work.
In short, to rate limit a box to 30MB/s
tc qdisc add dev eth1 root tbf rate 30mbps burst 10kb latency 70ms mtu 100000
The reason why we set mtu to 10000 is because of this.
To delete this rule:
tc qdisc del dev eth1 root
And to view current setting:
tc -s qdisc ls dev eth1