Here’s a list of resources, some just online and some offering offline training too:
Tyler.com Amazingly thorough!
Nathan Jorgensen used to work at Software Alliance Wales and while this site hasn’t been updated recently, there’s lots of good basic essential advice there: WPimpress.co.uk
Pootlepress Jamie’s company is Cheltenham based, but run workshops all over the UK. He also runs an online support community, and creates plug-ins. He specializes in the highly versatile Canvas theme, by Woo theme, so if you fancy becoming a Canvas User, then check Pootlepress out.