COO is the Chief Operating Officer and is responsible for running the day to day operations of a company. CEO is the Chief Executive (and the highest position in a company) who makes all the important final decisions that affects the company. CTO is the Chief Technical Officer, which a company may or may not have according what the company does. CFO is the Chief Financial Officer and s/he controls the finance portion of the business. CIO is the Chief Information Officer which is a recent development in the Officer 'circuit' (along with Chief Creative Officer).
A President of the company can be one of the Officers and s/he also deals with the day to day running of the business, but may not have executive powers.
All the Officer positions hold executive powers meaning they have the right to make decisions on behalf of the company and shareholders. They must also sign the annual report of the company if it is floated on the stock market. (And if anything goes wrong with the company's accounting etc, they have ultimate repsonsibility [see Enron]).
Hope this helps. (This is only a very brief overview of each persons positions and their responsibilities, as they may go above and beyond what the title describes).