cured vs uncured live rock

It's been a mystery to me, but what's the difference between cured and
uncured? Is one better than the other?

What's the "rule of thumb" so to say for the amount of LR for a tank? Is it
1lb/gal? or does it depend on the density of the rock? So far I have 10# of
Fiji in my 33g tank..

1 last thing, does anyone have a good website to learn about sumps and
overflows or a good book on them? I can't seem to find anything off
google.com.

Thanks,
SS