A CRJ 700 flight crew encountered roll axis system anomalies; declared an emergency and landed without incident at their destination.

Narrative

While on descent; with spoilers deployed; a quick rolling motion was felt. This sensation was followed by two Caution Messages; one for outboard spoileron and the other for outboard flight spoilers. The QRH was followed and it was discovered that a longer than normal landing distance would be required. I then calculated our landing distance using the numbers found in the Flight Standards Manual. After conferring with Dispatch and Maintenance it was decided that we would land on the longest runway and that just to be on the safe side we would declare an emergency. After notifying ATC; I called the flight attendants and informed them of the situation. I told them that we were expecting nothing more than a normal landing and taxi to the gate. I also informed them that I would make an announcement to the passengers to inform them of the situation and what they could expect. After all checks; announcements and procedures where complete a normal landing was conducted and the flight proceeded to the gate with out further incident.