EyeHawk, well I have not seen specifically a course on 2D Game Art, but I have many Evernote links to blog posts and such.
I do like deviantArt to look around and get some ideas.
Another great series of articles are the tuts+ tutorials and series with so much great insight with some listed below for your reference.
Digital Art for Beginners | Psdtuts+
Adobe Photoshop Tutorials from Beginner to Advanced | Psdtuts+
Game Development Tutorials from Beginner to Advanced | Gamedevtuts+
Photoshop Tutorials for Beginners | Psdtuts+
A great thing about the above links is that they refer you to many more links that can help you out.
Like you the only problem is finding time to go through it all and still have time to develop your apps and do all the other things that need to get done everyday.
I hope the above helps and let us know of anything you find especially pertinent, beneficial, and helpful.