Just spent some time transferring some short sections from a CD to my Motorola L6 with the help of a new USB lead and software downloaded from the Internet.
Check with whatever phone operator you buy the phone with though. For example, the SE K700i had support for mp3 ringtones out of the factory, but when Vodafone customised the displays to put on their links, they also removed the mp3 ringtone capability for some reason.