THERE ARE SEVERAL VERSIONS OF DIFF AIM PROGRAMS THAT ARE WEB BASED(WONT CHARGE YOU FOR TEXT WHEN U SEND AN IM), YOU CAN TRY
www.octrotalk.com
www.palringo.com
or u can download the program inside this post
OCTRO TALK IS PRETTY GOOD, PALRINGO IS GREAT IF YOU CANT GET THE ONE IN HERE TO WORK THOUGH
I use nero wav editor to make all of my ringers, its as simple as editing the song, saving it and copying it to your memory card