This legal Fatwa issued yesterday by the Ayatollah Montazeri (the most senior of the clerical class in Iran) is worth noticing for two reasons:
1) It is in its totality almost the same phrasing as Ayatollah Ruholla Khomeini used in his condemnation of the Shah's government of Iran during the Iranian Revolution.
2) It specifically calls the extant system of government in Iran "illegitimate".
If this doesn't knock the pins out from under those who still support the Khamenei-Ahmadinejad regime on a religious basis, nothing will. Whether that is enough to bring down the regime, though, that remains to be seen.