How is low/no alcohol beer made? I'm assuming that the beer is made normally and the alcohol is then removed, is it any more than just boiling it off? I've noticed that no/low alcohol beers' taste improved hugely a few years ago, is this due to a new technique?
There are a couple of ways to do that.
The two main "approaches" are to extract the alcohol afterwards or just don't allow the generation of it.
The extracting part can be achieved by filtering and reverse osmosis. Alcohol and water are getting sucked out and the "beer mass" gets re-watered. These steps may affect the taste quit a bit. A few brewers (especially in Germany) have developed a "top secret" technique to brew a alcohol free beer which tastes the same as "normal" beer - but most of these are "top secret".
Latest science experiements revealed a new way of brewing alcohol free beer, by just stopping the fermentation process. This can be done by lowering the temperature of the liquid containers.
Beers brewed with this technique tend to taste more sweet.
Both method have their up and downs so a couple brewers combined both: Less fermentation than usual and extracting the extra bits of alcohol.
I recently went on a tour of a microbrewery and had a conversation with a brewer afterwards. He said that their approach for reducing the alcohol content to legal "non-alcoholic" levels was to simply dilute regular beer with purified water.
It may be worth noting that the beer he was talking about was not designated for drinking, but for use in food production (beer-battered fish sticks, anyone?).
Reduced alcoholic beer has been developed by using an advanced development of the process known as vacuum distillation at low temperature (which is the most traditional and is less aggressive of any alcohol extraction methods), by using this sophisticated process the beer doesn't suffer any temperature or pressure aggression.