England is England.
England, Wales, Northern Ireland and Scotland all constitute the United Kingdom. Great Britain is practically the same thing - the words UK and GB are often used synonymously; in actual fact, I think they differ by a few islands between them... not sure.
[img]http://wwp.greenwichmeantime.com/images/europe/united-kingdom.jpg[/img]
Never
ever confuse 'England' with 'Britain' - the Scots and the Welsh tend to get a bit upset about these things.
Hope this answers the question somewhat