I think marketing strategy includes marketing plan. A marketing plan comes from a marketing strategy.
strategy is more tactical - i would say has general ideas and the markerting plan has more specific details on how you are going to implement those ideas
generally, a strategy is the way on how to reach a defined goal or set of goals. a (marketing) plan would be the operational measures which have to be taken.
lol, talk about confusing who cares? (that's my opinion, and I happen to have uni degree in that type of field... )
They are basically synonymous, call it whatever you want, but you need a good strategy or a good plan.
Strategy is general tactics and plan is step by step action to be taken to achieve goals.. clearer now? Next question please!