It seems that every time the Pope announces his intention to hold a consistory to create new cardinals there arises the question of when does a Cardinal-Designate become a Cardinal (i.e., could he vote in a conclave should it be needed, etc.)
According to Canon Law (Canon 351§2): "Cardinals are created by a decree of the Roman Pontiff, which in fact is published in the presence of the College of Cardinals. From the moment of publication, they are bound by the obligations and they enjoy the rights defined in the law."
So the question becomes, does the announcement (such as on Wednesday 17 October 2007) constitute "publication"?
The Holy Father indirectly made this clear in his introduction to the announcement. He mentions that he is abrogating “by one” the rule of 120 Cardinal Electors. The key point there is “by one”. For on that day there are 104 Cardinals under the age of 80 and thus Cardinal Electors.
He named 18 new Cardinal Electors. Thus giving us 122 Cardinal Electors if he intended the announcement as the official publication.
It should be noted that Cardinal Sodano turned 80 and lost the right to vote on 23 November 2007.
So, if the Holy Father intends to aborgate the rule “by one” as he clearly stated, then the official publication could not occur before 23 November 2007. (And, of course, 24 November 2007 is the stated date for the Consistory itself.)
Thus it becomes clear that the announcement is not "publication" - and so the Cardinal-Designates remain Cardinal-Designates until the consistory.