Okay, so what I do is preheat my oven to 350, place the nuts on an ovenproof plate, and toast for 5 minutes. At that point I check them, and most times cook another 2-5 minutes. It basically depends on how many you're cooking; I like mine lightly brown in color and with a nicely toasted aroma.

I'd use medium heat so they don't cook too quickly and then cook them in a dry stainless steel pan on the stove top for about 3 minutes, but do not leave their side. Stir or shake frequently. As noted in other comments, they should develop a lovely deep golden color (easier to see with pine nuts than other nuts). Although I assume that you just want them toasted, but if you're putting them in a salad or serving them with pasta, they're delicious cooked in a bit of butter.

Don't you love it when you get 2 different answers? Cooking time depends on the heat. I'm guessing pierino toasts them at a higher temp than kirsten, but the advice to watch for the smell will have you covered either way. This is true for all nuts: they have almost no smell raw, but develop a delicious aroma when toasted, which lets you know they're done.

One minute in a dry pan. Keep the pan moving and toss so that they don't burn.

It's more about watching for a good toasty brown color and noticing a nutty smell -- then you'll know they're done. It doesn't take long -- about 5 minutes on the stovetop and a bit longer if you're toasting in the oven, so watch them closely!