Noupe has aggregated a list of 60 Photoshop Tutorials from various sources. The list includes links to other lists of tutorials, so it’s actually a few hundred links and tutorials.
Some of them are directed specifically at creating digital art in Photoshop, like these 100 that I mentioned in a previous post (more here), and some of the ones here.
Others are more general, with effects, textures, patterns, downloadable brushes and PSD files, cheat sheets, keyboard shortcuts, actions and generally enough Photoshop links and resources to keep you knee deep in colorful pixels for several months.
Have fun, and don’t forget to come back up for air.