All the dividend earned from ELSS (tax saving mutual funds) are taxfree?

All dividends earned from tax saving mutual funds are tax free or some dividends from same schemes can be taxable if earned in sepecific cirstances (i heard that dividends from ELSS are only taxfree if u holding that ELSS for more than 3 months, like if i buy ELSS on 1st Jan 2008 then only those dividends will be tax free which will be declared after 1st march 2008 and all dividends declared before 1st march will be taxable for me. is it true?)