The Church of England and Episcopal Church are both members of the Anglican communion. This is a very large group of churches that comes together
in a synod under the leadership of the archbishop of Canterbury, and the Governorship of the Queen of England.
List of churches in the Anglican Communion can be found here...
http://www.religiousforums.com/forum/showthread.php?t=19306
On its foundation By Henry V111 You Would have found no difference in the Church or its theology with Catholics at the time, except that the pope was not recognised.
Henry remained theologically of a Catholic belief.
The changes were gradual under the influence of continental protestant churches who had broken away from Rome for Theological reasons.
To this day the services are very similar indeed to Catholic ones. this has become very apparent since the Catholics stopped using the Latin mass.
The words they now use in English, are almost identical to those historically used in the Church of England.
Over time and especially during the Commonwealth led by the Puritans The CofE became much more protestant in nature,
they did away with much of the imagery of the Roman church. On the restoration of the Monarchy many churches reverted to a more Roman style and belief.
To day the Anglican Church in England covers a very broad Range of practice under a single overall Dogma.
This ranges from very High Church (near Catholic) to very Low church ( near puritan), and every colour in between.
In some respects I have found The Church of England is nearer in sympathy to the Orthodox Church Than the Roman One...
This may have something to dowith the fact, that the ancient Catholic Church in England was based more on the Celtic church,( founded Prior to the year 200 )
which was monastic in organisation Rather than the See's of Bishops.
Married priests have Always been the norm in England ( as they once were in the Roman Church), and unlike most of the Roman church we were slow to change
and even quicker to revert on becoming independent.
The recent acceptance of Birth control, Abortion (frowned upon but accepted) Married priests, and the acceptance of Women Bishops.
has widened the gulf between the Roman and Anglican Churches
In comparison the differences in theology are minor. The main one being our understanding of the Host in the Eucharist.
In practice and theology we are unlike Calvinists or Lutherans. We base our selves more on traditional Worship than Theology.
There are some useful threads in the Anglican/Episcopal DIR Forum.