Here are a couple of sites and links I am consuming at the moment about KDP and self-publishing in general.
Add your own resources that deal with self-publishing.
There are probably others but Penguin has recently launched a self-publish community and service
You can publish through them and you work / files get replicated out to B&N, Amazon, Apple, Kobo etc
The free package offers 85% commissions through all channels (so for example if you re-distribute you get 85% of Amazon's 70%)
The top paid package at $399 includes editing, formating, cover, freebie coupons, + you keep 100% commission ( transparent re-distribution to Amazon for example)
I haven't tested this yet but they are solid, a Penguin group company, and I can see speed benefits to using them.
Smashwords is also a springboard. They have their own marketplace + also distribute your work to every channel that counts (at a higher cost though - you get 60% of the distributing retail price). Still, SW is currently the most popular publishing aggregator. Does not distribute to Amazon (which is a benefit since KDP is so easy to use)
Draft to Digital works like Smashwords
listen to the audio podcast bottom of page - good audio quality + seriously good advice. (Interesting about transitioning from e-book to "real" publisher at about 17 minutes.)
Lots of digital publishing info : law, news, sponsored events etc. Good!
Lots of examples on great e-book covers. And more.
The Kindle authors forum. Huge.
Not so much about self-publishing but lots and lots of news about what's hot with books today.
Amazon's forum - mostly for ref if you have troubles with KPD
Denver July 20 2013
Lots of UK publishing conference / event info.
Los Angeles September 27, 2013
New York january 2014
New York may 31, 2014
Book Expo America - this is the event I would have liked to attend! Lots of conferences & sit-ins.
Guy Kawasaki - How to Publish
Convert your manuscript into all sorts of e-book formats before upload to publishers