Hi!
I found an other program for extracting singstar songs, and convert them. (haggar (dot) pocketheaven (dot) com). I'm also working on a on-klick-singstar-extractor
By the way, have you heard of UltraStar? It's a sourceforge-project that looks just like Singstar. But it is for PC.
If you want help to convert singstar-songs to ultrastar you can post in my forum (fonsan (dot) org (slash) ultrastar).
See you!