How to use a rosemary plant in my cooking?

I purchased two rosemary plants in pots at the store. I hear they're supposed to have blue flowers in the summer, but these haven't flowered yet. Anyway, I was wondering exactly how you cook with them. If I want to use the fresh leaves, do I just snip them off and put them directly in my cooking? Do I wash the leaves first? I know you can dry them as well, but I hear using them fresh gives a better taste. Can I just pick off the sprigs and use them as-is?