I used this BHG garden planner online and printed it to my Paperport - cropped, added text and saved! Voila! Instant garden diagram!
I have plant labels spread from one end of my desk to the other, in an attempt to update my sophisticated ziploc baggie filing system (see below), and complete the metal plant labels for each plant.
The plant labels that come with plants from the nursery often break or fade. If this is the only information indentifying a plant, especially a new one to your collection, it is essential to keep that information. I collect tags in ziploc baggies, by planting area, and then retag the actual plant with metal plant labels, including the scientific as well as common name. Then I use baseball card collector sheets, filed in a 3-ring notebook to store the nursery labels. I might also flag the plant in one of my books for easy reference later.