I hate to do this since I know that I will get flamed unmercifully, but that article seems to clearly indicate that Intel is having trouble binning the 3.06. Why else would they be releasing the new stepping next month in the 3.06 only, but waiting for the rest of the speeds until June?
Apparently, the first 3.06GHz Pentium 4 processors based on the D-1 core are scheduled to be available on the 9th of May, while the 2.80GHz and below CPUs are set to come on the 27th of June.
The article is also incorrect about the 1.55Vcore in the multiple VID. This voltage has always been available in the 3.06.