Fall is a good planting time as is spring -- it all depends on the region.

I suggest you become familiar with your county's Extension Service office. Most likely, they have Master Gardeners who can provide answers appropriate for your area.

Use this interactive map to locate your county's office: http://npic.orst.edu/pest/countyext.htm

It's interesting that apples are perhaps the most sought after tree that home gardeners want to grow.

But growing your own apples is quite pricey when you take into account the costs and labor of planting, watering, fertilizing, and pruning, as well as treating for diseases and insects common in your region. It's cheaper to take a leisurely day trip in the fall to a local grower to purchase a lug or two of fruits.

So, after all that, if you still want to grow your own tree -- actually, it's trees, because you'll need a 2nd apple tree of a different kind which will polinate the first, and vice versa - the Master Gardeners can provide helpful info.