Update: New & Improved Chart!
Ever wanted to land at KSC reliably from low orbit? Then this is the chart for you!
NOTE: The x-axis is in units of 100,000 meters!
You must be more or less in a circular orbit before using the chart. Look up your orbital altitude on the x-axis. The corresponding y-coordinate gives you your "landing phase angle".
Basically, you want to burn so that your periapsis is at as close as possible to 0 meters, and at the given angle AHEAD of your target.
It's actually quite simple -- check out the example in the photo album.
Example Photo Album
If you have a station in a fixed orbit, you could mark the relevant angles on a circle of paper, and use it again and again. That's really the way to go.
Let me know what you think!