I've got some high resolution black and white jpeg images that I would like turned into transparencies. I know some good printers, but I was wondering if anyone has done this and could cut quick to the chase.

Images are black and white bitmap (only black or white, no gray) or they are grayscale (levels of gray from white to black)?

 

If you have Photoshop, and images are bitmap, you can open image, then select all and cut, then paste as another layer. Remove bottom layer. Now use either layer properties to make white (or black, whichever you're after) transparent in layer properties, or use magic wand to select colour you want to remove and click delete to make it disappear. Wherever it's transparent you'll see white/light gray chess pattern.

 

If image is grayscale, you basically do the same but would need to tweak the edges to make transparency borders softer.

 

Once you're done, save the image in a format that supports transparency (PSD, PNG,...).

 

Hope that's what you were trying to achieve?