I can only really speak for the US but I will try and answer as much as I can. Tho much of it will be with links to more informative information:
1) What you are talking about is called becoming a Local Exchange Carrier, or in the US usually a Competitive Local Exchange Carrier. AT&T has some information on this at the following site:
2) It would depend on exactly what you are trying to accomplish out of there. If you simply want to be able to provide telephone service I believe the page referenced above should give some idea. If you wish to provide Internet service there is more involved.
3) This depends on how much bandwidth you're hoping to provide. If you want to go down to brass tacks so to speak, you would need to either run your own fiber across the country you wish to serve, or purchase usage of existing fiber from a carrier. At which point purchasing the gear to actually handle the fiber and send communications over it becomes another expense. One would want to purchase a certain amount of routing equipment and fiber optic gear. If you're planning on trying to reach #4 you're talking about a minimum of millions of dollars as you would need locations around the country.
Here is some brief background on DWDM one of the technologies used to "create bandwidth" : http://www.broadcastpapers.com/white...1B3E01C9624CF9
4) Honestly ? You can't. At some point your traffic from your customers will need to traverse another companies network. There are ways if you are large enough that you can reach peering agreements with the larger carriers, but for the most part, especially when starting out you will need to purchase transit from a larger better established network.
An article on Wikipedia about peering with some good links to other aspects of providing internet access: http://en.wikipedia.org/wiki/Peering
5) I believe the link in the first response can answer this question better than I can