Rate limiting has now been by and large superceded by MQC (Modular QOS CLI). Hence if requested to rate limit a traffic flow the chances are an MQC solution will be whats required, as ever, close attention to the question specifics is required.
In this scenario i limit the traffic flow for returning web traffic to the LAN segment on connected interface fa0/0 to 512kbps.
ip access-list extended 100
permit tcp any eq www any
class-map HTTP
match access-group 100
policy-map HTTP
class HTTP
police cir 512000
int fa0/0
config-if#service-policy output HTTP
