iLoveTypography.com Beginning Font Creation

I Love Typography has a great two-part article for the would-be font designers out there. The first article begins with some suggested software for designing fonts (FontForge is free!) and moves the reader through basic ideation processes (hand sketches, tablet-drawing). The second article gives a brief overview of some font design basics - kerning, vertical metrics, and horizontal metrics. This is a great introduction, and I Love Typography has some suggested reading in the sidebar for further investigation.