lego.com legoclub.com :)
As Lego Halo is not a real theme, try browsing the Internet for sites that may sell custom Lego Halo items. Sites like Firestar or eBay are good at selling Lego Halo.
There are plenty of organizations that exist for the enjoyment of Lego fanatics. As well as the official Lego Club there are independent sites such as Lugnet and The Brickish Association.
No. Lego originates from Germany. there will be shops there but there are no massive supporters of Lego.
Sites like eBay, Amazon and Firestar are good.
There are no sites that allow you to do it online, but there are many sites that allow you to download software which allows you to make your own LEGO movies. Simply search "Stop motion software".
Yes.
I'm afraid Lego Batman sets are no longer manufactured any more. You can still by them though off sites like eBay and Amazon.
LEGO.com
for any Lego questions go to bricklink.com
Sites are not actually as good as they are ahead
I don't see any sites that sell Lego Christmas decorations. However, the following web site has instructions to make your own: http://www.nclug.us/2007/12/02/lego-christmas-ornaments/.