I feel your pain. Here I've got this brand-new, extremely cool camera with tons of modern functions that I am putting great effort into learning, and I spend most of my time during shoots jogging from one end of a playground to the other just trying to get the kids in frame, much less properly exposed. Who knew painting children's portraits could be such a strenuous occupation?
Well, I hope that AE lock stuff will eventually come in handy for both of us; I don't think I've used it yet in the five shoots I've done since my Digital Rebel arrived. The true saving grace of digital cameras as far as I'm concerned is being able to carry two 512 meg cards in my pocket instead of ten or twelve rolls of film for my vintage A-1. When I can shoot 250-300 exposures in an hour without stopping to rewind and load, I have to be doing very badly not to find eight or ten good ones in the bunch!