realistically it should be fine on an antistatic bag or wooden table.. you shouldn't really have any problems with static if you just use common sense.
And just to clear things up: placing the motherboard on top of the antistatic bag doesn't prevent static; the motherboard must actually be...
Actually, Yonah has a different pin-out than the other s478 and s479 (Pentium M's socket) processors. Yonah has its own new socket, s480 (different pin-out, but same number of pins IIRC). Also, an Intel 945 (or newer) chipset is required to run the Yonah chips because they are dual-core...