This doc should help you, it covers the Cisco 6500 series: Enabling NetFlow and NetFlow Data Export on Cisco Catalyst Switches
You have some videos there as well from our head geek: http://youtube.com/profile?user=solarwindsinc&view=videos
or more detailed, the Cisco Doc: Catalyst 6500/6000 Switches NetFlow Configuration and Troubleshooting
That thread is short and concise about how to configure your 6509: Netflow Config On 6509
BTW: You should move your post to the NetFlow forum or ask an admin to do so.