A Newb with questions, I am a newb. I have questions. Do you have answers? Options

[Nimblegrund]

I have long been a fan of the setting for Shadowrun. I have had a number of SR sourcebooks over the years, but I have only actually played shadowrun a couple times. Now that I have the new 4th edition book, I think sometime in the future I would like to run a SR game, but there are a few things I am not clear on. I might come up with more questions later, and if I do I will put them here.

1. I understand that the megacorps are kind of like countries in their own right... and a person can be a citizen of a megacorp. But how does someone actually become a citizen of a megacorp? Where do you have to be born? It's not like Ares Technology is a place on the map. What if you get fired? Do you lose your citizenship?

2. Why would anyone ever want their cyberlimbs to be wirelessly active? or their cybereyes? I kind of understand that it would be fun for the player to hack into some big bruiser's cyberarm and have him shoot himself. But wouldn't it be profoundly stupid to have your ARM be connected to the matrix? The explaination in the book doesn't sit right with me.

3. My brother would like to play a Technomancer rigger. How would this work? Are technomancer riggers at a disadvantage over the usual type of rigger?

4. Suppose I am setting up a run for my players. It is your typical get in/get out mission. What sort of challenges would I need to prepare for a hacker? I understand the goals: turn off the cameras, open the doors, turn off the sentries, get the data, etc. How do I know what sort of security measures to throw at the hacker?

5. This sort of figures into #4, but I recall previous editions descriptions of decking and I remember seeng maps of squares, diamonds and circles connected by lines serving as maps for decking and showing where nodes go and what they do etc. but this time around their description of nodes is very broad and the maps are gone. I feel like there was something I could have taken away from that.

6. This one I suspect I may get lambasted for, but... I don't like the idea of one player getting multiple turns while another doesn't. I remember from previous editions that all one would have to do to get a second turn would be to roll above 10 on initiative. I don't think that is true anymore, but I see that there are spells and cyberware that can give people more actions. Suppose I reduced any and all additional turns to a single (and I don't have my SR book with me right now, so I will borrow a term from D&D) "standard" action. would this break the system?

7. How do you interface with your commlink? One page describes a character who controls his commlink with a scroll wheel. I cannot possibly imagine surfing the internet with only a scroll wheel. How do they see the information they recieve? I noticed it mentions that commlinks can make holograms. So if someone is walking down the street surfing the matrix, is a glowing window floating in front of him? Is he wearing special shades? moving his commlink around like a mouse? How does he type? This is all presuming that he has nothing implanted in his head.