Newbies headed to the store can be in for a daunting task. You may be left scratching your head if your not prepared. You must arm yourself with knowledge people! I'm going to give you some links to get started but I would suggest using some other tools you may have at your disposal. Try your grocery store's website or even better talk to someone who works in the produce department. They are there to help and they are usually quite happy to do so.
When researching, you should not only try and find out what grows in the particular season you are shopping in, but also take into consideration your location. What is farmed locally, what has to be shipped in? Where does it come from? It may have come from Australia because of our opposite seasons, but you may be paying extra for all that shipping. Wouldn't it be good to know if it's better to buy something that was flash frozen at peak season or to get it fresh?
Check out these links for more info:Epicurious Peak Season Map-interactive area map
Wisebread-a small list that is a good starting point
Fruits & Veggies More Matters-extensive list of available seasonal produce
About.com- a seasonal list for the Pacific Northwest
Real Simple-what's in season for spring & how to choose good produce
Field To Plate- Links for seasonal produce in every state and/or region
Perhaps the greatest tool I utilized in an effort to educate myself in seasonal cooking came from New York Times bestselling author, Leanne Ely:
Saving Dinner-seasonal recipe menu mailers. Get a free sample menu mailer when you sign up for their newsletter. You will love it!
Saving Dinner Cookbooks-These books are set up by season. They come complete with meals for the week, shopping lists, nutrition facts, and side suggestions. My favorite book is the low-carb book. Many of the recipes in that book are my go to recipes for company. The many I have tried are all super fast and easy.