Has anyone here used them? I can visit a local book shop and find them on just about any topic, but I always notice its hard to find good computer books since things can so quickly become outdated. Is it better to always just look online instead?

Those are great if you are just getting started on a subject, but you will need to get something stronger once you get rolling. I bought websites for dummies and that gave me a good overall picture but I moved on to the "headfirst" series, which I thought was great.