Filtering Bad Web Content : Porno Sites

Dear Friends: I have a ProSafe Netgear FWG114Pv2 Router. It is connected to the internet via a Motorola Cable Modem. I would like to filter “Bad Web Content” so my students do not access “Porno” web sites. This specific router has got the capabilities to block “keywords” or even “web addresses”…But, how do I know what to block if there is millions of these sites out there. Is there a guide to follow so the computers can just browse the internet for intellectual eductaion only? I really don’t know how to set up filters…Could somebody help me please!
I sure appreciate all the help I can get! Thanks a million in advance!!!

Cordially,
jviso