Just to say, 3 months is the given time by google for the people to show off their sites and publicise them. The time is given so that people can try to get more and more high PR BL's. There would be a lot of difference in the PR update in a month and in 3 months
It also makes it harder for the black hat seos to guage the success of their techniques - if PR is one of the measures. SERPs are what really matter and they are fluid. Concentrate on them!
google knows better. only a few days ago was the last update, so another 3 months we will need to wait