While I realize a link between Jesus and Horus has been hotly debated for years and is still a point of contention, the list of similarities among myths in ancient Egypt, Greece and elsewhere to Christianity are almost too numerous to list. According to writer Joseph Campbell, the pattern, known as a monomyth, goes something like this:
A hero ventures forth from the world of common day into a region of supernatural wonder: fabulous forces are there encountered and a decisive victory is won: the hero comes back from this mysterious adventure with the power to bestow boons on his fellow man.
And so goes the Jesus tale and many, many others throughout antiquity.
For further reading, see the Wikipedia entry on Jesus and comparable mythology.