The new 965 south bridge can accommodate a pair of PCI-E X1 expansion cards, Gigabit Ethernet, 7.1 audio (via AC97), and four SATA drives with RAID levels 0, 1, and 0+1. SiS's new design retains the proprietary MuTIOL link between north and south bridge chips, rather than replacing this link with some adaptation of PCI Express. SiS separately announced the 163 and 163U wireless LAN chips with 802.11g support, but there's no mention of WLAN capability in the 965 south bridge.
The company says vendor samples of both the 656 and 756 are available now, with 656-based motherboards due to hit the market in May. No word yet on the timing of 756-based boards, so they must be a bit behind the P4 version.