Blaah, I'm probably generalising from my own (mildly dysfunctional) family experiences, though Lazycow seemed to be suggesting similar things.
I think it's v. easy when children are tiny and unselfconscious. We took my dd1 to stay with my cousin whose ds was the same as dd1 (3 at the time). They spent most of the holiday sitting in the sandpit, each chattering away in their own language, blissfully aware that the other child couldn't understand them. Occasionally one of them would pick up a phrase in the other child's language and repeat it and they'd bat it back and forwards, laughing hysterically. Family legend has it that I, aged about 4 and having just learned to read, picked up an English book and read it (in German) to my German cousin (who was visiting us in England at the time). That's the upside of kiddy bilingualism.
The downside? I think my mother spoke her native language with me very naturally when I was little, and since I'd spent the first few years of my life with her parents, I also spoke it very easily and naturally. Once I started school (in the UK) I remember realising that our family experience was not normal, and somehow wanting to be more like everyone else in my class (ie. not speak a different language at home). It also became v. difficult to speak about school experiences at home in my mother's language, because I lacked the vocabulary for things I'd only experienced in English. Round about that time I started to become quite self-concious about speaking German. I think my younger siblings felt this awkwardness even more, since they'd never grown up with German as a first language. After a while we did start passively resisting (ie. answering in English) which invariably provoked an argument. Which in turn made us quite resentful -- as a child (or an adult, come to that) if you want to tell someone something, then you want to be able to get on with it without being told that actually you should be using a different language, and that actually your grammar in the other language wasn't quite right because you were mentally translating from your first language. Etc.
It also led to disharmony between my siblings and me because my German was much better than theirs, which I inevitably used to play up to win the 'Mum's favoured child' award. Cue much kicking under tables, blah blah. And marital disharmony because my dad thought my mum was being ridiculous, and didn't really support her. My sister and brother hated being forced to speak German and actively turned against any use of the language.
It's complicated. I do know people who grew up bilingually who were happy with it, and I know other people who were not brought up bilingually despite having one non-native parent who resent that their parent didn't share the language with them. And others who just aren't bothered either way. I did need to use both languages, and my German is pretty much native speaker standard (or would be if I could spend three months there using it). And it is an important part of my identity, but I do also feel I was affected by never feeling I belonged somewhere 100%.
I think the situation of people in eg. an English-speaking family brought up in another country is slightly different, as is that of people brought up within a strongly bilingual community. And I'm not saying it isn't worth doing, particularly if one of the languages is your own native language. Just that it isn't straightforward, and there is a potential for conflict that made me decide against it. But in any case English is now so much my main language that it would have been quite unnatural for me to speak German with my kids, despite being quite convinced during my first pregnancy that I would.
I'm not really qualified to advise on practical books - my cabbage patch is more the neurolinguistics and cognitive end of things. And I'm sure One Parent One Language is the most effective way of going about things just that you need to be aware bilingualism won't establish itself automatically just on that basis -- you will need more extensive input from other sources, and that the eventual outcome will be very variable depending on your family circumstances and your child's personality.