Google Page Rank on New Sites

[guide2]

I wonder how the page rank is calculated for the new sites?

I have two new sites (one launched in December and the other one in November) both with PR-0. Both are indexed by Google (I've checked site:www.mysite.com); both have backlinks (not many - about 2-10) from relevant pages of other websites with good PR (4-7). Google PR prediction tool showed that the PR of these sites would be about 4-6, but it's still 0.

Can anybody explain it? Are there any chances they will get PR during this PR update?

Thanks in advance.

[steveb]

Displayed pagerank is broken, like the rest of Google.