A) - Web based training is okay, but it goes hand-in-hand with practical experience. You could pass the exam based on the information made available on the web, but when it comes to putting your positive test results in real-life practice, you may find you don't know anything at all. Theory and real-world practice always vary from one another, especially when it comes to repairing Macs. This is especially true when it comes to taking apart
Macs, something you don't learn when reading text made available over the web. (And is one skill set you must perfect to become an effective Apple Technician. If you know anything at all about repairing or taking apart PC computers, it's safe to assume you know nothing at all about taking apart Macs without prior experience, because they really are that different. You should see some of the disasters I clean up when a PC tech think he's qualified to take apart his 12-inch PowerBook G4.)
B) - Salary is between $24K-$38K, depending on experience and who decides to hire you. Yes, it really does vary that much. (And based on your location.) It is by no means a high-paying career to get into, so if you're taking this route, do it because you love it, not because you're saving up for a BMW. If you're brand-new to this area, I wouldn't expect a salary breaching much past the $30K mark, if at all. (I originally started under this mark.) Over time and depending on who you work for, you could make even more than $40K+ per year. But don't expect that on your first year on the job.
I work in this field (and am fully certified), and I can tell you I never walked into this career looking for fat pay cheques, but because I love the challenge and my passion for this kind of work goes hand-in-hand with what I've learned in this field through experience over the past several years. One thing you have to adjust to, however, is that no matter how hard you try, there will always be customers who never appreciate what you do for them, and in this regard, it can make some aspects of the job frustrating. However, if you have real passion and enthusiasm for this kind of work, as I do, the benefits will likely outweigh the occasional frustration with customers or a stubborn Mac refusing to cooperate regardless of what you do.
The best way to train to become an Apple Technician is to enter an internship with an AASP (if possible). Watch the senior technicians for a while, then start doing some work under supervision. Eventually, with the guidance of the senior tech's in the house, you will increase your skill set, get real-world experience and obtain real-world advice and tips from technicians who have been there and done that and aren't going by theoretical examples. Nothing is more valuable. In time, you can then get your certifications in order, and with the real-world experience gained through an internship, be well on your way.
Feel free to ask further questions, or PM me.