The facial hair applications used for television and film are called lace facial hair pieces.
The high end ones use a fine meshed fabric (like a window screen) with human hairs individually tied to the mesh (aka lace)
When an adhesive is applied, the nearly invisible mesh further vanishes into the skin, allowing for feathering and blending the hair into an actor's skin. This creates realistic hair lines that look completely natural.
You can also use a special double sided tape to help attach lace pieces, which saves some cleanup time. (removing the adhesive from the lace can take a bit of time)
The down side is that they are often quite expensive. The good ones cost around $300-$500 for a beard/goatee.
If you find a professional makeup store that caters to film and television makeup artists, they may be able to rent you the pieces.
I was working on a shoot a couple months back where I had to get 2 sets of sideburns, 2 goatees, and 2 mustaches for a couple of our actors. I was able to rent the pieces for a reasonable price from a special effects makeup shop that I frequent in North Hollywood.
The crepe hair and spirit gum technique works pretty well, but the application time can be between 1 and 2 hours, depending on how detailed you get with the cutting and styling after the initial application. They also do not hold up to close-up shots quite as well as lace pieces.
Hope that helps. Let me know if you have any other questions!