... 1. does it use the standard download functionality in php?what?, are you on crack...php has a download function? first I heard of it.
to download ringtones to a mobile all you need is:
WAP Enabled server (apache add-on)
A few mime types for WML, smaf etc.. available on the net somewhere.
Download NMIT from the Nokia website (in development section), use this to write and correct your WML
Now its pretty simple, its just like writting a normal php file just replace the HTML with WML, think your index file has to be .wml though.
To download ringtones as in midi or smaf files its basically just a normal link e.g. www.myserver.com/amidi.mid the server tells the phone its a midi (through mime types) and the phone does the rest.