Set the default route?

[Mike Missett <mmissett@cine-med.com>]

I seem to be having the same problem as some other people in
the mailing lists, namely, that the defaultroute for ppp is going
to eth0 when that's not my connection.  Advising somebody a
week or so ago John Hasler suggested:

"You probably have a defaultroute pointing to eth0 and pppd won't
replace
it.  Remove that defaultroute and ppp shoul work."

I think this is what I need to do, my question is, how do I do it?
I haven't figured it out from the lists, experimentation, or the
man page (although I probably should be able to from there if
I were a little less ignorant).  Any help would be most appreciated.
Mike