This data set contains the top speeds of a number of animals expressed in km/hr. 

Of course, all these speeds are simple estimates and have been derived from a number of sources listed below.  These must be estimates because there can always be some extraordinary animal in some species who can achieve a higher rate of speed than that observed by researchers.

Sources

1. Speed of Animals.com is a very interesting site which shows you not only the predicted top speed of various animals but also shows ho that speed appears to the animals of different heights.   In other words if you are only as tall as a mouse, traveling at one km/hr would fell like you were moving at a screaming pace.
2. Speed of the Impala was found at a-z-animals.com.
3. Speed of a guinea pig was given by answers.com.