Binabik: From what i can gather, most of the tweaks that Fasterfox used to make to about:config are built into FF 3.0, though i do not know if they all are. You can still make changes yourself to config, but its not wise to unless you know what you are changing
I will try to find out more about Fasterfox though, i know that most of the Add-ons that are not yet compatible with FF 3.0 is because the people that wrote them seem to have vanished lol