I can post my maps too, for comparison. I use Excel (originally made them in OpenOffice but I'm on Windows today), but make each box in the spreadsheet a square to represent 1x1 foot in the garden. I keep a template version with the color coding, and another with the plant names in it for each growing season. This format makes it easy to add notes (as you can see in the first image), and I also keep another tab with planting dates and other info.
Here's winter 2011. Back yard only, so you can read the labels:
Zoomed-out view of my entire property:
Colors: black=buildings, gray=paved surfaces and my two mini hoop houses (not sure why they're the same), dark green=perennials, light green=annuals/biennials, brown=unplanted areas (mostly walkways or heavy shade)