Can somebody point me in the direction of a good resource for learning about heads?

I would like to add some power to the car, and have been researching options, and heads seem like a great way to add some power, but I don't know where to start looking to put a head/cam package together.

 

I have read through some articles such as that, but I'm afraid I need a "ls1 heads for dummies" article. There's a nice sticky explaining cams, but nothing for heads.

For example: I know therer are 215 heads, 205 heads, 243 heads, 5.3 heads.... They can come as "as cast"....

I know what heads do, and I know what people can achieve, but I'm at a loss as to what's what!

 

Your best option to learn is to lurk, read, and study these forums.
When you ask to be pointed in the right direction it helps by knowing things like what car, which engine, rear gears, tranny (converter), any other mods as well as intended power goals/usage. Include budget also so we know how much of your money to spend.