I was unable to follow any site that featured a series of images showing the knot in various stages. The drawings were just too difficult to follow. At some point, I'd always lose track of what went where.
Fortunately, there are some really good instructional YouTube videos.
I like the Southern drawl on the narrator's voice (especially at 0:29 when he says "cinch it down"). If you've got a wedding coming up, an easy way to practice without incurring suspicious laceration marks on your neck is to tie it on your thigh.
What about wearing a bow tie outside of formal wear? Personally,I think it's a tricky thing to pull off, especially if you're not a:
Now, I suppose I'm being just a bit unfair. Interestingly enough, corporate culture seems to tolerate the bow tie, especially in the U.S. Every big American law firm seems to have one middle-aged partner in a corner office who wears bow ties as a matter of course. He usually has a collection of more bow ties than you can count, and is overall well-dressed. The bow tie is his thing (e.g., he's known as "the guy with the bow-tie").
In recent years, thanks to the rise of preppy-chic, the bow-tie has made a bit of a resurgence.
As for me, I don't think i could pull off the bow tie in a casual setting. Because it's such an exceptional piece of clothing, it just feels a bit too affected for my liking (much in the same way as does wearing wool scarf indoors).
I did see a Dior(?) ad in men's magazines a few months ago, which featured a guy in black pants, white shirt and a black leather jacket, and a black bow tie. Unfortunately, I couldn't track down that image, but I did think it was a pretty cool look.