About a week ago, GlassFacts.Info had an entry on glass powder. Here's a simple and effective powder technique.
Take a piece of sheet glass and draw on it with lines of glue. Plain white glue (like Elmer's) will work fine. CMC glues (like Bullseye's GlasTac) will work too - just be aware that the viscosity of the glue will affect the final appearance.
Now, take compatible glass powder and sift it heavily onto the glue. Keep adding powder until the glue no longer soaks through to the surface.
Once the glue has dried, tip the sheet glass on edge and tap gently so that all the excess powder (the stuff not glued to the base glass) falls off. You can reclaim the extra powder for future use.
You can repeat the above process, adding additional powder design elements each time.
Fire the glass as desired – tack-fused if you want the texture of the lines to remain or full-fuse to achieve a smooth surface. Make sure to vent the kiln while the glue burns off. A soak around 900F for this purpose is a good idea.
As always, make sure to test colors and firing schedules before investing a lot of time and glass in large project. Light colored powders tend to get lost when fused to darker backgrounds.
See the first link below for an example of a finished sample.