Ron welcome to the board, itís great that your wife has expressed an interest in FF, and there are a number of ways you can go.
You and your wife might start off by checking out a friendly fly shop for a brief casting lesson, and then depending how that goes consider a certified casting instructor, fly casting school or casting clinic/beginner program offered by a club.
I have no first hand experience with this shop, but Iíve heard good things about Mason at the Salisbury Fly Shop. He offers free casting lessons to customers, and is pretty wired into the Chessy SW FF scene and should be an excellent resource for you:
Salisbury Fly Shop...You one stop for Saltwater/Freshwater FlyFishing supplies
Casting instruction- in addition to fly shops, you might consider a FFF certified casting instructor. You can do a search for one near you here:
Find A Certified Instructor
Hereís a womenís fly fishing club located in your area. They offer beginners clinics, group trips and might be a good way for your wife to meet some new fishing buddies, and learn in a woman friendly environment.
For both of you, the Federation of Fly Fishers has affiliated clubs offering casting clinics, group outings, and most have mentoring programs. Typically they are very friendly environments for newcomers and are very encouraging: Locate a Club
And, Trout Unlimited Chapters often have casting clinics, and many members do both FW and SW fly fishing. Some also have mentoring programs:
Council/Chapter Search | Trout Unlimited - Conserving coldwater fisheries
In addition to the Orvis and LL Bean and Wulff schools that would involve significant travel, there are some more local options as well.
If you and your wife are interested in FW trout fishing, Dusty Wissmuth has a very good reputation and is a wee bit closer: Dusty Wissmath's Fly Fishing School
Another excellent school geared specifically to SW Flats Fishing is run by Sandy Moret in Islamorada. To get the most out of it though, it would be good to have at least some of the basics down in terms of casting fundamentals, but it is a great (though spendy) option down the road, and instruction is with world class anglers.
Online Fly Shop - Florida Keys Outfitters - Fly Fishing School, Fly Rods, Fly Reels, Guided Fishing
Hope some of this helps, and we all wish you and your wife the best.