That's a lot of questions.
In about a year, I'd be able to point you at the Business Analyst Body of Knowledge (see my .sig), but we're still in the process of developing it. IN the meantime, try some of the following:
Ambler, Scott W. The Object Primer: Agile Model-Driven Development with UML 2.0, Third Edition. Cambridge University Press, 2004.
Larman, Craig. Applying UML and Patterns: An Introduction to Object-Oriented Analysis and Design and Iterative Development, Third Edition. Prentice-Hall, 2004.
Robertson, Suzanne and James. Mastering the Requirements Process. Addison-Wesley Inc., 1999.
Wiegers, Karl E., Software Requirements, Second Edition, Microsoft Press, 2003.
Most of these books don't cover business process design, unfortunately. Still, they should give you a start. The Wiegers book is probably the best overall introduction to software requirements in general, while the Larman book does the best job of showing how to go from requirements to design and development.
