Fall is THE time to plant bulbs like Daffodils, Tulips, Crocus, Hyacinth, and many other spring-bloomers.
Many people also ask about summer-blooming bulbs, such as Dahlias, Lilies, and Gladiolus. Those varieties become available in the spring for planting.
Bulbs get planted the season or so prior to their bloom-time. Or, another easy way is just to come to the nursery in the fall and the spring and we will have exactly what you need at the correct time =)
Most spring-flowering bulbs like at least 4-6 hours of sunlight. They also do very well under deciduous trees, since the trees will not have leaves until after the bulbs come up.
Bulbs can rot in over-watered, or poorly-draining soils, so make sure to mix in compost for nutrients and drainage before planting. Give the area a quick weeding while you do it, you'll thank yourself later!
Pointy side goes up. Easier said than done with some types of bulbs. If you can't tell which is the pointy side, look for the side with roots, and put that face down. Worse case, plant the bulb sideways and let geotropism (your word of the day) take care of the navigation.