First of all, there is nothing quick about becoming a business analyst.  It takes planning, effort, and determination to become a successful BA - but, of course, if you love what you do getting there (growing) is part of the fun.

Here are quick answers for you:

1. See this high-level explanation of the various roles and titles a business analyst may have: The Roles of the Business Analyst 
2. Check out this page for one view of what a business analyst does (remember that no two BA's jobs look the same): Snapshot of Business Analyst Profession
3. While every business analyst will surely use emails and documents to communicate, the value of the business analyst comes from their ability to communicate verbally and facilitate working sessions (requiremetns workshops) with business experts to understand their problems/goals and elicit requirements.  In addition, an effective analyst knows how to use visual techniques to communicate information and elicit requiremens including: context diagrams, process flow diagrams, decision tables, UI mockups or wireframes, prototypes, etc.

I would highly suggest that you get a copy of the BABOK which provides a great overview of the skills, tools, and techniques commonly used by business analysts.

Another great resources is the The Software Requirements Memory Jogger.

- Adrian