Ok I came up with a card thru window, very effective, and I am already using it. The only problem is I do not own any card thru window on the market, so I have no idea if this is an original thing, or if it has been invented before. Does anyone know where can I find this information, how do I know if this has not been invented before, how can I copyright it?

Thanks
Marien

Marien,
The best way of finding out if you've created something new or have just re-invented the wheel is to ask experienced magicians. Find a few people on this board that have a couple hundred posts and are professional magicians. PM them asking if they are familiar with card through window tricks and if they'd be willing to look at your method to see if it's already been done. If they're willing to look, send them your trick. Chances are that a professional with a large number of posts is going to be ethical and not rip you off.
Copyrighting a trick won't give you the protection you think it will. Read my article at http://www.odonnell-law.net/C1776251671/......dex.html

The only Card Thru Window effect I know the secret is the Peter Marvey' s Card Thru Window you can get it in http://www.penguinmagic.com/product.php?......eID=4504
And there is also David Blaine's Card Thru Window at http://www.free-magic-tricks.net/resourc......dow.html

You have also the John Kennedy method:
http://www.johnkennedymagic.com/scripts/......oduct=12