Can someone compare these two fish-eye lenses?

Http://cgi.ebay.com.au/58mm-0-25X-Fisheye-Lens-f-Canon-450D-500D-550D-G10-G11-/170565749445?pt=AU_Cameras_Photographic_Accessories&hash=item27b682cac5

and

http://cgi.ebay.com.au/Super-Wide-Fisheye-Lens-Nikon-D40-D40x-D60-D70-D80-/330494803250?pt=AU_Cameras_Photographic_Accessories&hash=item4cf3067d32

My camera is a nikon D60, but I know I can get filter adaptor rings.

Both are Adapters and not the REAL fish eye lens.
If you have decided to buy one of these, go for the second one which is going to fit on your camera without any additional accessory.

Does the D60 hqve a DX sensor? Fisheyes don't work well because the sensor is smaller.

These are converters, or adaptors, not a proper fish eye lens - they fit on an existing lens.

The pros: they're cheap, and once of you tire of the fish eye effect, it won't leave you wishing you hadn't spent loads of money, coz you didn't

The cons: a fish eye image is often circular (with black parts around the edges) - everything will be distorted - - to make a half decent image you usually have to crop it.

If you were to buy a real fish eye lens, obviously it would cost you lots, and once you get bored with it you'd regret spending all that money.

I can't open your links, but from words and numbers within those links I assume that the Canon is a screw-on adaptor, but that the Nikon is possibly a true interchangeable fish-eye lens. Either way, it seems that you should do some more research to define whether you want an adaptor, or a true lens - the latter would give better quality, but is likely to be much more expensive. If a true lens, you obviously need to get one with Nikon lens mount for your Nikon.