Realtek released driver version 3.42 for their ALC-Series soundchips. It supports all types of ALC soundchips from ALC100/P to the new ALC655 and all OS from Win9x to XP.
MSI has CMedia 9738/39 drivers 5.12.01.0029 for Win98SE/ME/W2K/XP available.
Both the Realtek and the CMedia chip are widely used as OnBoard sound solutions on mainboards.