DVI-D only supports digital output, and doesn't even provide pins for analog, so a simple adapter that re-wires the pins from a DVI-I/DVI-A port to VGA won't work. As far as I know, none of the new graphics cards released in the last few years or so have the hardware to support analog output.
However, you can get an "active" converter that will convert the signal from a digital connection to analog VGA, which can be found on sites like Amazon for around $10 or so in the US. There are different ones for converting the signal from DVI-D, HDMI or DisplayPort.
You might want to first double check if your monitor happens to offer another port on the back to support one of the digital connections using a different cable though.