1. No, it is not necessary (though it might make the learning curve less steep if you have had some experience).
2. It depends on your preferred style of learning. A lot of colleges, universities, and professional training centers offer short introductory classes. There are also some great introductory books with CDs. You may be able to find some on-line tutorials as well.
3. One great tool is the Macro Recorder. If you turn the Macro Recorder on, and perform a bunch of steps manually in Excel, then stop the Recorder, you can view the code you just Recorded. This is a great way to see how VBA views what you are doing. Even now, many of us experts will start certain tasks with Recording some code (we don't have all this code stuff memorized!), then editing the code to clean it up (usually, to make it more dynamic).
And as always, it you have any specific questions, we are always here!