You need to vist a site which supports "media descriptor" files. which are a special file to "tell" the phone what to do with the media.
There are some commercial sites which can help you for this.
see some other forums here for them (sanyo 8100 or TX95c ones)
how it works....
The phone is instructed to go to
for example to get the ringtone.
the phone collects that file and follows the file instructions EG:
Content-Name: Scribe NZ HipHop
and collects the ringtone from:
And Voila. A ringtone on the phone.
(the above site won't work as the server does not know what to do with a "GCD" file)