I have a C331t, and yes it is possible.  I have not downloaded any as
the network I am using right now does not allow text messaging, voice
mail notification, or any other digital features (except caller id, but
that works on the analog networks here).  I am on the preferred nation
plan and I moved, while in contract, to North Dakota, and am roaming on
an inferior Cellular One Network.  I have programmed monophonic ring
tones into my phone using "My Tones".  Visit the following link:

http://mww.moviso.com/cingular/app?class=Cingular&proc=GetMakeInfo

or go to www.cingular.com and on the left hand side, under "Getting
Started", click on Downlad ringtones.

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