First, note that it should be 'to school' not 'to a school'. 'To school' means that you're talking about the usual school which your child attends. If you say 'take my kid to a school', it sounds as if you are choosing a school at random (as if you might drop him off at a different school every day - any school will do!). 'To a school' prompts the question: 'which school?'. As for the verb, there is a difference. 'Take my kid to school' just focuses on the journey from home to school with the child. That's all. It's a neutral statement. 'Get my kid to school' is not so neutral. It sounds like a chore, and it puts the emphasis on the achievement of the task (taking the child to school, leaving him there, saying goodbye and then heading off - phew! Job done). The suggestion here is that there might be something difficult about achieving this. Perhaps the kid doesn't want to go to school or perhaps the weather or the traffic is bad. Or perhaps you've just got a million things to do every morning and everything you do is an ordeal.