image from cultofmac.com
may be is an issue according to the HP Mini 311 Support page. People are in the process of testing initial mods made to VoodooHDA source.
I'll update when I get my vacay starting Thursday and will give you guys, well um, an update. :)
Update 1: Only audio breaks on 10.6.3 but, if you absolutely really need to 10.6.3, VoodooHDA can be used in the interim, until a better fix is found. Bottom line: stick with 10.6.2 for a while.
FYI: Audio support for the Mini 311 in 10.6.2 and below was made possible via DSDT modding. This involved legacy AppleHDA which is now unsupported (if I heard, erm, read right) in 10.6.3. If the VoodooHDA patching becomes successful, it would prove even more beneficial as boot time can be reduced.