I received a gift of a Adafruit Wave shield and after assembling it using the excellent instructions on the Adafruit site I could not get it too work. The problem was the SD card would not initialize. After trying two different SD cards, checking the forums, and re-checking all my solder joints I could not get it too work. I decided to test the SD cards with an ethernet shield I also have for the Arduino. The SD cards refused to work in this shield as well. After a bit more reading I discovered that the issue was the SPI ports on my Arduino Mega are in different locations. The following fix also works for the Mega 1280.