Check your travel insurance. Unless you have a bare-bones policy, it's likely that your policy will cover trip cancellation for political unrest. If so, contact your insurer for the process to claim a refund. If you don't have insurance, you're at the mercy of Smartours and whatever policies they have regarding when they cancel a trip.

From smartours and travel insurance sales organization website:
smarTours reserves the right to cancel any tour, for any reason, prior to departure and cannot be held responsible for any damages resulting from said cancellation.
In case of such tour cancellation by smarTours, a full refund of the monies paid to smarTours will be offered. There is no additional liability.
Any dispute arising from any tour, itinerary, product or service provided by smarTours as well as any dispute arising under these terms and conditions will be governed by the laws of the State of New York the state or federal court located in New York, New York.

I suspect most travel companies are following the same procedures as SmarTours. Overseas Adventure Tours posted this note on their website 2-5-11: Due to recent events, we have decided to cancel all departures to Egypt through 2/28. We are in process of notifying all affected travelers with this information, as well as with options for rescheduling their trips. ... As of February 2nd, all of our travelers have left Egypt safely and are in the process of transferring home. For all departures in March and beyond, we are closely monitoring the situation on the ground with management in Cairo, Aswan, Alexandria, and Luxor. If there are any changes to our ability to safely operate these trips, travelers will be notified immediately.
Travel Guard is considering the events in Egypt as Civil Unrest and, therefore, not covered by their insurance. However, a Travel Guard rep suggested that each affected traveler submit a claim since each would be reviewed on a case by case basis.

I have written GaryCA privately (Hi Gary) a few days ago, but it might be worth repeating here for the benefit of others.
Friendly Planet is a tour company that offers many destinations and itineraries that are identical to or similar to smarTours and it's possible that the two companies may share the same supplier. Friendly Planet is giving travelers on their cancelled Feb., March and April tours to Egypt the option of either rescheduling the tour for a later date or cancelling the tour altogether, with a refund of deposit and payment in full. On Friendly Planet's website, their exact wording regarding the latter option is as follows:
"3. If you wish to simply cancel, just let us know. We will refund your deposits and payments in full. We regret not having you with us at this time, and we hope that you will decide to join us in the future."
Based on the wording that TravelCenturian quotes from smarTours in her message on this thread, as well as the policy of the similar tour company, Friendly Planet, I believe that if you request that smarTours fully refund your money, that they will do so although it may not be the choice that they would have preferred.
That all being said, the only hitch might be that the two tour companies use different airlines for their Egypt tour. smarTours uses Egyptair, so it may all depend on how willing that airline is to refund the monies that have been paid to it by smarTours. Indeed, this may be the very issue that is holding smarTours up from being more specific with you at this time.

Start putting everything thing in writing ASAP, and make sure there is no small print you are overlooking that allows them to get out of their 100% full payback obligation. Send them a letter asking for your money back with some sort of mail delivery guarantee. Then keep the pressure on them. I lost a $600 deposit after 9-11 led to a canceled Red Sea trip and the tour company went into bankruptcy - they later settled for $34 dollars in bankruptcy court, but luckily my credit card had already made good on the full lost deposit payment.
I think the travel industry would do well to put all deposits in a secure escrow account, but often they use them like a Ponzi scheme to fund other more current obligations so they don't have YOUR cash to give back to you when something goes wrong. I had to learn this the hard way myself.

Interesting New York Times article <il>Egypt Tourism and Cancellation Policies</il> dated Feb. 10, 2011 at:
http://travel.nytimes.com/2011/02/10/travel/10egypt-travel.html?smid=fb-...
In particular it says next week EgyptAir will decide whether to offer full refunds to passengers holding tickets for March and April trips.
Presumably EgyptAir’s decision is what smarTours is waiting for.

My tour was also cancelled.:( too bad! It killed my excitement!

Any dispute arising from any tour, itinerary, product or service provided by smarTours as well as any dispute arising under these terms and conditions will be governed by the laws of the State of New York the state or federal court located in New York, New York.