I stumbled across new California tax form FTB 3536, which requires California LLCs to pay estimated LLC fees by June 15 of the current tax year, starting with tax years beginning on or after January 1, 2009. A 10% penalty if you underpay; a safe harbor if you pay estimated equal to or greater than the LLC fee for the preceding tax year.
this is, of course, in addition to the annual LLC tax of $800.00.