My apple wood pipe, with photos, is on this thread:
http://fairtradetobacco.com/showthread.php?432-Making-a-quality-tobacco-pipe.
PIMO does offer a small book (112 pages for $22) on pipe-making:
http://www.pimopipecraft.com/book.html. It will show the basic concepts and appropriate drill bit measurements and angles, etc., though I have not purchased it.
About corn cob pipes
I have one corn cob pipe that I've smoked (mostly for straight burley) for about 40 years. The bottom (core of the cob) tends to burn out after a few years, but back in 1973 I reinforced it with a clear yellow epoxy on the bottom only. They taste awful for the first 3 or so bowls, while you are charring the interior. The only brand to even look at are the Missouri Meerschaum corn cobs. The plastic bit which comes with a corn cob will tend to bite through, after a few years--or sooner, but the company offers cheap replacements.
Since the stem is often made from a maple dowel, its bore (the smoke hole) tends to be larger than those in the sturdier briar pipes. This influences the smoking characteristics. Many come with a disposable paper stem insert filter, which is useful during the break-in period, but which I remove permanently after that time.
For reasons unknown to me, corn cobs smoke burley beautifully, but don't seem to have the right flow characteristics for English-style pipe tobaccos.
My most enjoyable pipes are briar. My Turkish meerschaum pipes are made with uncomfortable bits for clenching. I tend toward half-bent pipe shapes, since they tend to keep the condensation (which is quite bitter on the tongue) from coming up into the bit. But perfectly straight pipes (like a "Canadian") smoke well if held at a slant. I do like the Stanwell half-bent bulldog pipes, available in the $70 range. If you smoke a pipe regularly, you may find that having a number of pipes allows one to fully dry after smoking, while using the others. If you intend to smoke both English-style tobacco blends and aromatic blends, then you should use different pipes for the two groups. Each of these two tobacco styles will spoil the pipe for the other.
The trickiest thing about learning to smoke a pipe enjoyably is the right packing density for various tobaccos, since it is different for different cuts, different case, and different tobacco varieties. Most beginners "over-puff," and burn the tip of the tongue. "Sipping" just enough to keep the tobacco lit is a reasonable approach. The packing density will determine how much you have to puff to accomplish that.
All that being said, just about any pipe can be smoked with pleasure, once you become accustomed to how it smokes, and how to pack it.
Bob