[expert] can't open display under ppp

[Jonathan Oppenheim]

I am able to get ppp running, and i am assigned a local IP address
dynamically.
I can run netscape locally and things like that, but can't get a 
remote server to open up an x window on my local machine.

(I get the "can't open display" message")

i ssh over to a remote server.
i can, if need be set the display (i use bash) to the local
IP address I've been assigned by typing DISPALY=xxx.yyy.zzz.ww:0.0

before I ppp, I type  (on my local machine) "hostname <some word>" 

and i have the line "ALL: .phys.ualberta.ca" in my hosts.allow file
(where .phys.ualberta.ca is the domain name for the remote server)

but when i type "xmaple" for example (after establishing an ssh
connection) i get "can't open display"

is there something else i need to do to tell the remote machine how to
open my display?

thanks!
jonathan