I was taught the same way maddog suggests, use an earth point rather than the earth of the battery.
I was also taught to keep the assisting car running during the procedure which obviously means I don't disconnect the positive terminal. Starting in general takes a heap out of even a good battery momentarily, add to that any voltage drop across the leads (it may not be that much but it will be there) and the assisting battery if not in the best shape can quickly end up as stuffed as the first. If the engine is running at the time of cranking and the assisting battery staggers you can lift the revs of the assisting vehicle up to keep the recharge current of the assisting battery higher. Of course this can require two people but in most cases if there is two cars there is two people.
As with any procedure there is many theories, which one you subscribe to is probably as much about preference as it is about who you trust more when it comes to story telling. Do a hunt around the net and you'll probably find thousands of people who use either of the above ways and some who think it's all crap, you might even find some people who think they can do it telekenetically (it is the net after all). The best bit of advice would really be not to stick your tongue on the sparky bits, it may only be 12 volts but it's not the volts that kill you