i have 2 ftp servers proftpd and vsftp
 

how to choose vsftpd for default server?

disable proftpd ?

yes i need disable proftpd, and how?

Depends on which distro you are using

CentOS 5.0 final

To just stop the service, you should be able to do:

service proftpd stop

To stop the service from starting at boot, you should be able to do this through the gui (if installed).

On Ubuntu for example, you would go to

System->Administration->Services

If you untick the service it should stop it from starting at boot.

You can also use the command

sudo sysvconfig &

Or you can use svcadm on other systems.

Look at the man pages for those commands and you should have everything you need to enable/disable services.

If you don't use the gui, "chkconfig proftpd off" as root

If you don't want to use proftpd, then rather uninstall it. Should you ever need, you can always re-install it.

You can run both proftpd and vsftpd, but you have to configure one of them to listen on ports other then the standard port 21. The ftp clients will have to access that specific port then.