I've started singing backing vocals in my rock band, and in the new blues band I've joined I'll be singing a few leads. I've always been able to sing in tune, but thought my range was a bit naff and I didn't have as much control as I'd like.
I though about getting some singing lessons but they're WELL pricey, so I thought I'd get a tuition book of some sort. After digging around a bit, and finding a lot of rubbish books about classical singing I came across the book below.
The author, Roger Kain, is head of the Voice Department of the Brighton Institute of Modern Music. The book is superb, and aimed at rock singing for both males and females (with specific exercies for each). It covers the theory, types of voices, ranges, power, tone etc and even screaming. This guy knows his stuff, and it's all about what the rock guys and gals have done to disprove all the classical singing theories. I've been running through the basic exercies for a few days (which take about an hour) and I can feel a difference already. I now understand more about how the voice works as an instrument, and why some notes were/are easier to reach than others.
Totally recommended, and at £13 including two tuition CDs it's an absolute bargain!
http://www.amazon.co.uk/Complete-Vocal-Workout-Step-step/dp/1844920038/ref=sr_1_1?ie=UTF8&s=books&qid=1240480897&sr=8-1