frac have a look on moneysavingexpert.com, he always has threads about this type of thing and is pretty good at sussing out the market and recommending when and when not to switch. he also has a number of comparison sites for making utility switches, most of which not only compare price but also which are the greenest companies,which are best in terms of reliability etc,etc. some of them also offer incentives for when you switch, the one i have used for the past 3 years gives me ?15 every time i change gas and electric companies and at no cost to me.well worth a look.