Downloadable Program To Make Gauge Faces?

No special software is needed.  Any drawing program or photo editing software will work.  Even windows paint.  Do a google search in images for cockpit guages vector images.  Up will come tons of images of individual guage faces.  Save and bring whichever images you like into your image editing software.  make sure the rulers are turned on in the software and reduce the image so that the faces measure down to what you need, usually 1-2 mm in diameter.

You can print the gauges on paper or decal paper and using a micro punch, punch out the faces and glue them in the correct locations and put a drop of future over it to make it look like glass.

Another way I do it is if I am using photoetch or I can scan in a cockpit guage cluster part or even make one with styrene with holes drilled out for the guages, I will scan it in, copy and paste the guages into the correct locations and then print the gauge faces as one print out.  then line it up behind the plastic or metal part and glue in place and then add drops of future to make it look like glass. 

I do not find accurate guages to the aircraft I am working on, I just use what ever looks close as I work in 48 scale and by the time the image is scaled down, there is no way to tell. 

You don't even need to use vector format. I just use jpeg as downloaded from Google Images.  Any of the graphics programs can resize to the scale you need with sufficient accuracy.  I google each time of gauge until I find the appropriate one, create a new image file and copy the rescaled images into that.

I sometimes scan or copy the instrument panel or decal the kit provides.  If it is a decal or film of the panel, I white out the instrument faces, print the remaining black image which then leaves the print clear, on view foil transparent sheet. I use that to cover an image of the panel, which gives a sort of dimensional or overlay to cover the instrument face images.