go to your MySongs page and press the "Share" button next to the song you want to turn into an MP3. select the "Send as Attachment" option. you can email yourself the song from here. it'll be in .AIFF format, which is less compressed than MP3. your iTunes should recognize this format, but if you want it in MP3, you can convert it with iTunes.
You must have an older version of LaDiDa. Make sure to download the free update from the "Updates" section in your App Store. Let me know if that works!
it works on any song, any language, any genre. it creates original music to whatever you sing.
I believe there was a problem with Facebook Connect yesterday, which is now resolved. Are you still having trouble with this? Let me know!