Intel's quite sucessfull dual-core Celeron SU2300 clocked at 2x 1.20GHz will get an update, although the details are still a bit fuzzy. We are talking about very succesful entry level, around €/$ 500 notebook market.
Celeron SU2300 is doing very well and it's a great alternative to Celeron single core 743 as it definitely offers more raw power.
The replacement in this market segment will come from Montevina or Calpella platform but Intel doesn't want to disclose that at this point. Celeron 743 should stay in this market segment at least until Q2 2010 and might get a speed update at later date.
All in all, despite the great specs, it looks like Core i7 620UM and Core i7 640 UM will end up in notebooks that will cost more than thousand euros / dollars, much more than most of you want to spend on a notebook in 2010.