There was a PageRank and Backlink update today 01/11/08 (January 2008). It appears that while PageRank update was very subtle the Backlink update was more interesting. Some new sites experienced no PageRank to their homepages while showing some PageRank on the subdomains. Of interest, Google is now showing PageRank in the Google Directory and has this to say about it:

"Unlike other directories that can only list web pages alphabetically regardless of how good they are, the web pages in the Google directory are ordered according to Google's view of their importance. This means that the most relevant and highly-regarded sites on any topic are listed first ... not buried deep within a list of other pages" (citation)

For further information you may want to read: Google Update From DMOZ data?