Rates for jobs can vary from sector to sector and from job to job. One of the main things to understand about a photographer's income is that it is usually derived from two parts, from commissioned work and from selling stock photos. Most successful photographers will have built up a healthy stock library of their own images and these can be used to generate a steady income. It is extremely important that copyright laws are observed so make sure you read all about copyright for photographers in our Legal section.
The National Union of Journalists have produced an excellent fees guide for freelance workers including photographers. As well as pay information there are also lots of useful hints and tips about protecting your work, what should be in your work agreement etc - a valuable resource. Have a look at the suggested rates here:http://www.londonfreelance.org/feesguide/index.html