William, I know your trip is eminent, and I put my google skills to work.
This site had some guidelines that make sense to me from my own travel in Egypt.
This is a matter of personal discretion. Although bills normally include a service charge, it is customary to tip in restaurants and other places that cater to tourists. You may use the following as a guideline:
* Porters: 50¢ per bag
* Waiter/Waitress: $1.00 per person (dinner)
* Chamber Maid: 50¢ per person, per day
* Driver/Guide: $6.00 per person, per day
* Cruise Staff: $3.00 per person, per day
* Bus Driver: $2.00 per person, per day
* Group Tour Guide: $5.00 per person, per day
* Private Car Tour Guide: $10 - $15 per person, per day
Tipping is considered by locals to be a part of their normal remuneration and some may approach you for additional "compensation". There is no need to be intimidated by the request, nor should you feel pressured to pay more than recommended. If you become uncomfortable by any behavior you encounter, please advise your tour escort.
I have always paid drivers at the end of a trip as we are parting. I sometimes put the money in an envelope to leave with them. However, if your driver changes throughout the trip, you'll need to "tip as you go".