Scaling MySQL on Amazon Web Services

I've recently started working with a large company who is looking to take one of their heavily utilized applications and move it to Amazon Web Services.  I'm not looking to start a debate on the merits of EC2, the decision to move to aws is already made (and is a much better decision than paying a vendor millions to host it).

I've done my reasearch and I'm comfortable with creating this environment with one exception, scaling MySQL.  I havent done much work with MySQL, i'm more of an Oracle guy up to now.  I'm struggling to determine a way to scale MySQL on the fly in a way so that replication works, the server takes its proper place in line for master candidacy, and the apache servers become aware of it.

So this is really three questions:

1. What are some proven methods of load balancing the read traffic going from apache to MySQL.
2. How do I let the load balancing mechanism know when I scale up / down a new Mysql Server?  
3. How to alert the master of the new server and initiate replication in an automated environment?

Personally, I dont like the idea of scaling the databases, but the traffic increases exponentially for three hours a day, and then plummets to almost nothing.  So this would provide a significant cost savings.  

The only way I've read to manage this sort of scaling I read here on slides 18-25:
Has anyone tried this method and either had success or have scripts available to do this?  I try not to remake the wheel when I dont have to.  Thanks in advance.