evrey phone i have ever had has a way to make your own ring tones.
what does the bb curve support and can i make custom ring tones right on the phone

Your BlackBerry supports MP3's.

You can make ringtones of any MP3 with any MP3 editor. I personally use WavePad which you can find easy on google. It's not free but has a free period to test it. I think you'll find it easy and intuitive.

I own a BlackBerry site that has free ringtones, themes and wallpapers. I also host those for other developers and most use MP3's for what you want.

If you need any help, feel free to email or PM me here. I'm new here but will be around from time to time. Not to advertise intentionally.. ok a little maybe but.. you can find my site at BlackLightThemes com. I'll answer questions BB related there or here