A lot of evidence points to Jesus actually being born in April, one such piece being the bright star was caused by either a conjunction of several planets, or a nova that occurred at that time too. So, if you believe the bright star over Bethlehem, April is most likely. And it was a few years BC too.
The reason we celebrate it in December is either because a) Christianity is an offshoot of Judaism, and Hannukah is also in December, or b) It was an attempt to stop people acknowledging the traditional Pagan holidays.
I think Christmas, whilst seen by many as a cultural thing now, should always retain it's Christian roots. The reason being, the sheer level of stupidity of many people means that a lot of people won't know WHY they are giving out presents and eating turkey!
My mum was having fun in December, she is a primary teacher at a CofE school... A new family, muslim, arrived in town and for some reason decided to send their kid to the Church school! Wouldn't have been a problem, but they insisted that their son not learn anything about Christianity... yes, exactly!
Can you imagine trying to shroud one boy from 300 children all shrieking about Christmas? I have Muslim and Jewish friends who celebrate Christmas, although most of the Jewish friends also eat bacon sarnies!
In 1999, I was watching the news and they had gone out asking the public "Why will it be the year 2000?" Presumably they had decided just to show the complete f***wits, one woman said "Well, 2000 years ago someone decided it was the year nought!". Whilst that was stupid in itself, I couldn't help but remember the number "nought" wasn't invented until the 2nd century AD, and wasn't treated as a proper number until the 7th century.
The 1999/2000 new year was all a big fuss anyway, I didn't notice much going on in the 2000/2001 new year, and that was a whole new millenium!
Anyway, my rather tenuous point is, there are a lot of stupid people who will be celebrating Christmas and not having a clue about it's origins. You don't have to believe it, but you should at least be aware of it!