Mid to late February. They can't start printing them until after the new Secretary and Treasurer have been appointed and gotten their Senate confirmation.
Remember, the series date is when the design was approved, not when the note was printed. Unless there is some huge political push to print notes with the updated secretary and treasurer, don't expect to see them too soon. Numbers is the guy who would know best though (from past experience as he actually tracks the printing runs)
If I had to guess, I'd say sometime next fall, but that's a complete wild guess at this point. Before the new series can go to press, we'll need *both* the new Secretary *and* the new Treasurer to be in office. The Secretary, Timothy Geithner, will surely be confirmed within days of Obama's inauguration (quite possibly within hours, given the economic situation). But the Treasurer is really a rather unimportant official these days, and so that nomination won't be a priority at all; it could easily take months for Obama to get around to picking someone, and more months for the Senate to get around to confirming her (or him? but there hasn't been a male Treasurer since the '40s). Once both signatures are available, it typically takes the BEP two or three months to prepare the new master printing plates, make working plates from them, and get the first of the new-series currency through all the steps of the printing process. After that, typically one additional denomination comes on line every month or two. So at the absolute earliest, if everything goes as quickly as possible, we might see a few Series 2009 notes rolling off the presses as early as April, and we might see the last regular production of Series 2006 currency around end of this year. More likely, everything will be delayed several months beyond those dates, waiting for a Treasurer to be installed in office. (In the extreme case, Series 1993 didn't go to press until April 1994, because it took Clinton over a year to even nominate a Treasurer.) And when the new-series notes finally *do* get into production, it'll take several more months for them to reach all areas of the country. They'll first turn up in one or two isolated areas, and then gradually spread, but there are always a few regions that take much longer to see them--basically, if a given Fed district has a large inventory of currency of some denomination, then they might not get any new shipments of that denomination for months at a time.... So even if Series 2009 *does* manage to get into production as early as April, many of us won't see the notes in our pockets until midsummer or later. Under a more typical timeline, with production beginning in late summer or fall, it's quite possible that some areas of the country would see little if any Series 2009 currency before 2010.
