x11-ssh-askpass is an X11-based passphrase dialog for use with OpenSSH.

To utilize this service, you will need a private SSH key in $HOME/.ssh/
If you log on using kdm, then just create a $HOME/.xprofile with the 
contents of /usr/doc/x11-ssh-askpass-1.2.4.1/xprofile.sample

If you are launching X from console (with startx), then you can edit 
your $HOME/.xinitrc to source the $HOME/.xprofile or just add the contents 
of $HOME/.xprofile to $HOME/.xinitrc to it.  Of course, there are other
acceptable ways to accomplish the same thing - gurus can roll their own.