SingStar dev head Paulina Bozek has confirmed that the harmony mode announced for SingStar Vol. 2 earlier this week will be made available for Vol. 1 owners. Phew.
"The new Harmony mode will be available as a free upgrade via the PlayStation Network," she said in this Q&A. "It will be compatible with the specially selected duet tracks. Once the upgrade goes out, we’ll be making more of these songs available in the SingStore, and there is a great selection on the vol. 2 disc."
Plenty more through the link.