How do I get ringtones on Cingular Flip?

I recently bought an AT&T Cingular Flip phone, and I would like to download ringtone MP3s.  However, there is no way to transfer files from a desktop, so I'm wondering how to get the downloaded files onto the phone.  Is there any way to send an email attachment as an MMS, for example?  Or if I emailed them to myself, would I be able to use the phone's browser to access my email and download them as email attachments onto the phone?  Any help would be greatly appreciated.  Thanks.