Are "computational biology" and "bioinformatics" simply different terms for the same thing or is there a real difference?
I found this post by Russ Altman quite good. Below is his opinion about the two similar but distinct fields:
Computational biology: the study of biology using computational techniques. The goal is to learn new biology, knowledge about living sytems. It is about science.
Bioinformatics: the creation of tools (algorithms, databases) that solve problems. The goal is to build useful tools that work on biological data. It is about engineering.
Just as a note:
This is just one persons opinion and I have heard many other definitions for both of these terms. For example, one person I know mentioned that he believes computational biology is concerned with very theoretical research such as NP-hardness (ie. articles published in the Journal of Computational Biology). Other people think that bioinformatics is an applied field that is essentially using already published tools.
Bioinformatics is a broad field that interfaces a variety of life science disciplines (biology, genetics, biochemistry, biophysics, etc) with a variety of quantitative sciences (mathematics, statistics, computer science, engineering, etc). Bioinformatics techniques typically involve developing and applying software and algorithms to computationally intensive biological questions, such as those common in structural biology, genomics, sequence analysis, and systems biology.
Some scientists draw a distinction between the term bioinformatics and computational biology. While these areas indeed broad and diverse, these distinctions in terms are not consistent or well-defined.
Case in point: @GWW's answer cites two different definitions, while another has already been suggested in response to his answer (as a comment). More definitions are sure to come from additional answers, comments, and edits. None of these definitions are necessarily wrong, but in the same way none are "right" as there is no objective way to determine which of the definitions is "better" than the others. If you were to ask 5 experts in the field, you are likely to get 5 different definitions.
Computational Biology - usually involves creating a model (software or other logic) where you attempt to shed light on some process of biology by building information flows using known physics/chemistry/biology --- (how to cells divide ? -> build a biomechanic model of mitotic spindles ...) --- You are building up complexity in your model to simulate biology to ever increasing levels of accuracy
Bioinformatics --> measure biology then analyze the data --- biology already has the complexity --- You are attempting to understand this complexity by identifying patterns in measurement data
Both of these fields drive research efforts to create better sensors used to measure biological processing