can CNAMEs and MXs coexist

[Joel Miles]

> Why not do:
>
> miles.ods.org. IN MX 10 miles-update.ods.org.
> miles.ods.org. IN MX 20 <your secondary mail server>
>
> You can also have:
>
> www.miles.ods.org. IN CNAME miles-update.ods.org.
>

Does this mean that I have to create a new zone record for
www.miles.ods.org?
I cannot directly edit my zone files while using ODS.org, so I can't do
this:

www.miles.ods.org IN CNAME miles-update.ods.org

in my miles.ods.org file.  It thinks I want to do this:

miles.ods.org IN CNAME miles-update.ods.org

Please help!