Not much here yet.
Things to do before going live:
Maybe check out the proposed sections...
LearningSo you want/have been forced to learn PHP?
NamingNaming things
RFC CodexDiscussions ideas for how PHP can be improved, why some ideas haven't come to fruition yet.
MerchPHP related things to buy
SystemSite system stuff...
InternalsInfo about PHP core development
Oh, and there's the system page