I looked at the first link, and I have to say that the footprint depicted in the photos there looks very, very fake. It is perfectly understandable that creationists might confuse it for a real footprint, because they obviously have never looked at their own feet before.
Here is the picture in question:
The most striking feature of the footprint, to me, is its incredible flatness. The heel and part by the toes should be pressed down more, because that is how weight is distributed when we walk. The part in the middle shouldn't be pressed down very much at all. The website says that these areas are pressed down as they should be, but if they are the picture sure doesn't show it.
To illustrate, I found this photo on Google Image Search of a fresher footprint.
You could do some handwaving and say that these problems are caused by erosion. If that is the case, however, the toes shouldn't be so clearly defined. In the above photo of the new footprint, you can see that the smaller toes are hard to make out, if you can even differentiate one from another at all. The "fossil" footprint, however, looks more like a sock with toes sewed on. The toes are all equally perfectly preserved.
These problems make me come to the conclusion that this particular footprint was carved by someone who wanted to make a footprint in a piece of rock, but didn't know much about feet. I don't know how old the rock is, but the footprint is new. Its shape reminds me of fake footprints of Bigfoot, where someone simply cut out a piece of plywood in the shape of a big foot and stamped it into the mud. Even creationists should be able to see through this.