There could be!

This could explain the multiple doctor theories. Maybe this has something to do with the Doctor losing the Tardis in 'The Lodger'?

Doesnt the doctor get blown out of the Tardis in the lodger ?

He is in the filming we have seen, but they could FX over it. Maybe Van Gogh goes in the tardis at teh end of this weeks episode, they go to Amys Wedding day, it explodes, spreading Van gogh paintings everywhere. in The Lodger, we see the Tardis land then explode (again, 2 parts of time). The Temporary tardis is built by the end of the lodger, and then we get episode 12 and 13, and we have the proper tardis back at the end of them.

Every crack? Its just one crack isn't it?

No, but there's a piece in every box of new Gallifrey-o's! Collect the set!

Dammit, i wanted to make that joke

In all seriousness, i think the cracks all lead to the same place.

Except we know that they don't. One leads between the Atraxi prison and Amy's house, and one connects the fish-vampires homeworld to Venice. Unless you want to go with a philosophical explanation that everywhere is the same place viewed from different angle, I don't see how this would work.

Besides, the fish-lady said that there would two types of crack, through some they saw other worlds, through others there was only silence. Presumably these are the cracks in space and the cracks spilling time energy.

I think the ones that the Dr is encountering do though.

There seems to be two type of crack, one which leads to other places, i.e the one in Amy's house, the one that the fish people went through, and the ones that seem to make people non existant.

What i mean is, how could the fish people or prisoner 0 go through a crack, and not stop existing, unless when you go through a crack you possibly travel to an other reality and stop existing in the other?

Also, oddly, how could the dr stick his hand in the crack and be ok, where anyone else that gets near seems to be sucked into non existance.

I think the cracks have been caused by different pieces of the TARDIS splintering off.

It has been argued (see DWM 420 for the latest example) that the TARDIS must be assumed to be infinite in size.
(Incidentally, it was subsequently pointed out that the Doctor in "Logopolis" stated that he had jettisoned 25% of the TARDIS.
While the concept of 25% of infinity is a bit problematic, you would still be left with infinity afterwards, no matter how much you chucked out!)

If the TARDIS is infinite, there would be an infinite number of pieces if it fragmented, causing an infinite number for cracks in the structure of space and time.

It's not the passing through the crack that destroys your existence, it's the time energy pouring out of it. Sure, it doesn't explain what causes it to start seeping out after the Doctor stuck his hand through - it also doesn't explain why the Doctor is content to leave it seeping after it takes Rory. Maybe there's an intelligence on the other side we don't know about? Someone with a plan?

I think you just answered yourself!

Correct - it is the one crack, but existing in all places and times at the same time (according to the explanations we've had so far).

If I was the Doc..

...I'd get a saw..cut off the bit of the TARDIS that corresponds to the bit he found (or make an exact replica)..blow torch it a bit ...

...then chuck it into the next crack he sees.

He woudn't need to worry about the TARDIS blowing up then.

That reminds me of Baldrick in the fourth Blackadder series carving his name into a bullet - assuming there is always a bullet with your name on, Baldrick wanted to own that bullet, thus saving himself. Baldrick's wonderful logic is much missed

The bit of tardis that the doctor has already found, is from the little door that the police box phone is in. This makes me wonder if the tardis is a lot less damaged than it appears. They might have "only blown the bl***y door off!"