Ask HN: Design for a Software Guy?

I've been writing software for more than 6 years now, and I've realized, somewhat painfully, that I can't design my way out of a paper bag. Are there any good resources out there about graphical design geared for a programmer? Are classes in 'Making Art with Photoshop' worthwhile? I understand the ideals of good user interface design, but when I go to mock up something for a personal app I hit a wall.