MySQL University is a series of free web seminars. Each week (on Thursdays) you have a unique opportunity to learn something interesting from MySQL developers and professionals.
MySQL University sessions cover wide range of topics including server administration, extending MySQL functionality, or just tips for better performance of your queries.
The sessions are conducted using DimDim, a web based conference tool build in Flash. It works really good even if your connection is not the fastest one.
During the session, the presenter will show slides and talk about the topic (so it's pretty important that you can understand spoken English), and you and other participants can ask questions using built in chat.
I strongly recommend you to take part in 'live' sessions as it is pretty unique experience, but if for some reason you can't, then there is archive of past sessions, often with flash recording, available at MySQL University's home page.
On the same page you will also find more detailed information on participation, as well as a schedule of upcoming sessions with abstracts and presentation slides, to help you decide if particular subject will be interesting to you or not.
There's also a Google Calendar with MySQL University Schedule available, to which you can subscribe.
From now on, I will (if time permits) post here on PHPfreaks about upcoming sessions that might be interesting for an 'average' PHP developer.
The one that takes place next Thursday is titled 'Scalability Challenges in an InnoDB-based Replication Environment' and seems to be directed more to server administrators. If however, you run your website on a VPS or a dedicated server, you might as well take a look at it.
Added Feb 1, 2009
The archived session recording is available here