Developer Living Memory released an 11 part tutorial series for their excellent LayR app. He also taught me a new British term: Lurgy, the definition of which has made me want to listen to a 1950's British Radio Show starring Peter Sellers.
This has been an immensely educational and edifying video series and I haven't even started watching them!
These videos cover nearly all of LayR's main features.
There are also lots of hints and tips that might not be so obvious just by playing around with LayR's UI or reading the manual.
Some are very short, only a few minutes, others such as the Layer Editor and Arpeggio Sequencer videos are up to an hour long.
With perfect timing the Great British Summer Flu Lurgy also decided to attack me as I was doing these vids so please excuse my narration as I was pretty much working through a thick haze!