Navteq has finally released the updated navigation CD's for North America - version 2005.1. Individual CD's can be ordered online for $129 each, plus shipping & tax, at
http://www.navteq.com.
Interestingly, Navteq is no longer offering the complete 8-disc North American set directly to end-users.
Reportedly, though, complete sets can be bought by dealers. Not sure what the pricing will be for complete sets (they used to be $189 for a complete set from Navteq).
No word on when updates will be available on DVD.