Are you wondering if you are able to send ring tones TO your phone? Sure you can. From any ring tone service (such as
Free Ringtones from Phonezoo: Make and Download Free Ringtones, Free Mobile Wallpaper and Play Free Games) just download them to your phone via text message and you can assign them to a contact or use it as a notifier.
There are a couple of really good threads here about setting up your files for that and I won't steal their thunder, but you just need to mount your phone to you computer and add files to the MEDIA folder on your SD card. Do a search for adding ringtones and you'll find some good stuff.
Good luck!