Today IDG announced 2010 Macworld moved from January to February 9 - 13, 2010. The location will remain at the Moscone Center in San Francisco, CA. I spoke with several developers, exhibitors, and attendees at this year's Macworld and the one point everyone agreed to was that having the event the week after New Years and the same time as CES was madness. I think the move to February was a good thing and should make it easier for attendees and exhibitors alike.
Free Expo Hall registration for Macworld 2010 will remain open, for a limited time, so if you are thinking about it, go register. I've been to several Macworld expos and for me the experience has always been defined by the community, not the Apple booth, so start making your plans now.