From the folks at Botanical Interest Seeds:
Whether you carve your pumpkin for a Halloween Jack O'Lantern or plan to us it for baking, be sure to save the seeds for roasting. Pumpkin seeds are rich in Vitamins B, E, and fiber. Homemade baked pumpkin seeds taste better and are healthier for you than the ones you buy in the store, because they are fresher and have less salt.
As you scoop out the flesh from your pumpkin, remove as much pulp as you can from the seeds. Rinse the seeds and spread out to dry on a clean dish towel. Spread seeds out evenly on a cookie sheet. Spritz them with a little olive oil and give them just a sprinkle of salt. (Additional seasonings can be added like garlic powder, chili powder, seasoned salt, or Parmesan cheese.) Bake at 350 degrees in the oven for 10-20 minutes, or until they just start to turn light brown. Remove and cool. Store in an airtight container.
(P.S. --- All winter squash seeds can also be roasted in this manner.)