Just thought I'd post this since it seemed confusing during our install.
To config our 6509 for netflow data to be sent we added the following commands.
mls flow ip full
mls nde sender version 5
ip flow-export source blahblah
ip flow-export version 5
ip flow-export destination blahblah portblah
This will send netflow data for all routed interface on the router. No need to add 'ip route cache flow' or any other command to each interface.