Which fisheye lense is better?

Don't say they both stink.

1.http://www.amazon.com/Zeikos-ZE-1858F-definition-attachment-Warranty/dp/B001XW67LU/

2.http://www.amazon.com/Zeikos-ZE-3437F-definition-attachment-Warranty/dp/B00275G10E/

or

3.http://www.amazon.com/Zeikos-ZE-3252F-definition-Fisheye-Warranty/dp/B00275G104/

please say why. And are they compatible with a nikon d5000?

They do both stink. They're not real fisheye lenses. This is a real one: http://www.amazon.com/...000144I30/

They are adapter lenses which screw on top of another proper lens which is mounted on the camera. Unlike real lenses, they do not replace that other lens entirely. To be fair, these adapter lenses are an ok way to find out if fisheye views are what you are really into without spending a fortune for a peoper one. Expect poor image quality and vignetting though.

I could only open the first link. If that one will work with your lens depends on which one you have. It is compatible with a 18-55mm kit lens as it supports a 52mm or 58mm filter thread (this kit lens has 52mm).It would not be compatible to a 18-105mm kit lens as that one has a 67mm filter thread size

Edit:
Meanwhile i could open the second link… That one is for 37mm filter threads, so it won't fit at all, no chance whatsoever.

The first one will give the widest view. You can figure this out by multiplying the 0.18X * the focal length of the lens you will be putting it on

Since it is a screw-on attachment it does not matter that you have a D5000, but that your lens has a 52 mm filter thread

Those are semi-fisheye adaptors, not true fisheyes. Of course they all stink.

It doesn't matter what you get, they all degrade picture quality. I say get the cheapest (I never bothered clicking your links). The lens will be treated as a toy anyway. A true fisheye lens may cost more than the camera itself.

They are sub-par filters, not true lenses. They produce mega vignetting - a real fisheye lens does not (unless it's a Sigma circular fisheye).

I suppose you could crop it to get rid of the vignetting - but then why not just crop yourself a 2, 000mm lens too?

A true fisheye looks like this:

These were taken with a Nikon AF 10.5mm f/2.8 DX fisheye lens.

Notice that not only is there no vignetting, but it also maintains the original aspect ratio of the photo. Notice the horizontal aspect is different than the vertical - in other words, it is not round. This is sometimes called a "diagonal fisheye".

You are just wasting your money. Save up until you can afford to buy a bona-fide fisheye lens.