This site can give you a taste of the huge variety of Corporate and Executive communication out there. If you are interested in this topic there are many, many sites you can access.
Communications consultant Steve Bowman gives a run down of various kinds of business writing and how he has made a business out of Business Writing. In the last few years there has been an explosion of these type of businesses on the net.
A good general introduction on how to get started as a business writer.
A simple template for generating formal business letters, designed for non-English speakers but useful for everyone.
A definition of a memo and an explanation of its structure.
The components of a memo with examples of contents.
A basic guide to writing reports can be found at this site. Explore.