I briefly attended a webinar on the use of MySQL proxy last week called, "Designing Scalable Architectures with MySQL Proxy." I say briefly because about 5 minutes in I was called away for an "emergency." So, I'm very happy to see that this absolutely excellent presentation and all it's related information has been posted on the web. Here is the starting point, the presentation itself:

http://datacharmer.org/presentations/webinar_proxy_jul2008/mysql_proxy_scalable_arch.pdf

That was a very entertaining slide deck. Here is a nice aggregation of links to the information as well.

If you are into MySQL, MySQL Proxy, and scalability this is a DO NOT miss.

Enjoy!