The only hard source on this is a tiny paragraph in this month's new Game Informer, so take it with a grain of salt. It's long been established that Nintendo didn't bother to tell any third parties about the Wii MotionPlus peripheral until their E3 press conference this year, which means that basically nothing hitting in Q4 this year or even early 2009 is likely to support it.
The word is that LucasArts is hopping mad with Nintendo about this, since one of their Q4 titles for this year - Star Wars: The Clone Wars: Lightsaber Duels - is the sort of title that would benefit tremendously from 1:1 motion input. Instead, the "ultimate lightsaber combat game" is very likely to ship with swordfighting controls inferior to those found in Wii Sports Resort (on top of being beaten to lightsaber combat by No More Heroes).
If Nintendo had shared the tech with them earlier in the development process, then Lightsaber Duels could've shipped as one of the first titles with full Wii MotionPlus support. Instead, it's looking more likely that LucasArts and possibly other third-party publishers are simply not going to support the peripheral at all.
