First off, as always: http://www.youtube.com/watch?v=9ulwV4XPyno
So a couple of people showed interest in learning how to Boomkin and I am happy to help! Admittedly I'm a little rusty since I've been bearing so much as of late, but I know where all the good resources are 😀
Speaking of resources, probably the biggest, most important thing for a boomkin is having a good resource bar in an easily seen location. I use Cyous' Astral Power Pro Bar WeakAura. It's great. It shows you how much your cast is going to add to your astral power, and if you're going to go over 100, the text in the bar turns nice and noticeably red. Boomkin doesn't have a real "set" rotation and is more of a 'build resources without overcapping and without wasting resources' sort of class.
I also use this weakaura by Gebuz. Mainly for it keeping track of capping on moon-moon charges. I'm really bad at noticing when I'm on 3 charges so I needed something big that lights up when it happens.
Gebuz is one of the big go-to's for Boomkin information. He has a great guide that is updated frequently.
Based on my own experience (pre-7.1.5 anyway) I would suggest generally starting out with a single target build. It's much easier to get a handle on. The talent choices for Boomkin allow a wide variety of playstyles, so it's best to keep it simple at first. It's really easy to pick a bunch of talents that sound cool but don't have synergy and you end up with a frightful mess.
I'd suggest something like this. Nonetheless, now that 7.1.5 has significantly buffed Boomkin AOE, they are major beasts at it and don't require as much weird talent fiddly-ness. Fury of Elune for example is a pretty cool talent, but you'll murder your dps if you have no idea what you're doing with it (or even if you have half an idea).
The new Boomkin AOE rotation is called 'memekin.' Generally the talent set-up is something like this. Restokin (a resto and boomkin resource site) has a very nice guide on it. I myself am still figuring out how to memekin well - it is pretty fun. My biggest issue with it so far is that I completely forget that Stellar Drift lets you cast while moving whenever you're inside of your starfall. Don't be like me. Be like the good Boomkins.
The person (Raphael?) that runs Raidadvice.com is a Boomkin main and frequently posts articles related to boomkinness. A particularly useful one is Balance Druid Encounter Notes.
I will post more as I think of things! Or if people have any general questions.