Here are some of the main differences. "The Eastern Orthodox Churches reject the teaching of the surplus merits of the saints and the doctrine of indulgences. The use of carved images, except for the crucifix, is forbidden. Purgatory is denied. In the Roman Catholic Church all beneficed clergy must be celibate, whether they are in monastic order or not. In the Orthodox Church those who are engaged in parochial work must be married, though they are debarred from the higher offices. Another striking difference is found in the administration of the mass, for the Roman Catholic Church allows the laity to partake of the bread only, the wine being reserved for the clergy, while in the Orthodox Church both elements are received by the laity. Further, in the Orthodox Church the elements may be administered to infants immediately after baptism, while in the Roman Catholic it is postponed till adolescence, though not necessarily till after “confirmation”. Also Orthodox Church worship may be conducted in the vernacular; the Roman Catholic service is often read in Latin". source: Handbook of Denominations; The Byzantine Patriarchate, by George Every.

Where did you get your information on the Catholic Church? There are at least two things i noticed you have the wrong information on. The first being that the laity are not allowed to partake of the wine in communion. This is not true. The laity are allowed to partake of both the bread and the wine during communion just as the clergy are. The other thing was that children are not allowed to partake of communion untill adolecense. This also is not true. While it is true that infants do not recieve communion, a child does not have to wait untill adolecense. In the Catholic Church a childs first communion usually takes when the child is around the age of 7 0r 8. Of course this can vary. i know of one child who had his first communion at age 5. -Angie-

The major differences revolve around matters of polity and around matters of doctrine. The Orthodox churches generally do not accept the Pope as head of the Church (apart from the few in communion with Rome.) The Orthodox churches reject the filioque clause in the Nicene Creed.