Here are some general thoughts about your questions.
(
)
What do you have to do to maintain the Tele #?
Typically use it every now and then, OR pay the monthly subscription if you choose a paid-for service.
Can you make it so your Inbound Tele # is synched up to were you live?
Typically yes, especially in the US.
How much more or less secure is using Skype versus a Cell Phone or Land Line??
Landline (assuming PoTS): zero security. As long as someone has access to the wires, you can be wiretapped with a simple phone and alligator clips.
Cell phone: in 2G, some security, but very easily defeated as most carriers don't force call encryption the standard can support in order to save on cost.
3G, somewhat more secure. With proper but cheap equipment, though, you can be listened to.
Do I have to worry about hackers and viruses?
On an Android smartphone, yes. On iOS, possible, but unlikely. Using a computer-based VoIP client, possible. Though if you download it from the official provider website, there shouldn't be any problem.
What about the NSA or even Microsoft spying on me??
They will spy on you, whatever technology you choose. They placed backdoors in Skype (the protocol was not so secure anyways), compromised encryption key generators to make them easier to crack, and have the technical means to crack open any encrypted conversation at the consumer level. While you can't avoid being spied upon by the NSA, you should worry more about being spied upon by private companies. Microsoft is one, but Google surely leads the pack when it comes to information gathering.
What are my payment options for Skype?
Do I have to use a credit card?
Most providers will require you use a credit card, although some may use PayPal as an option.
And does Skype or Google Voice require a whole bunch of intrusive information like AT&T and Verizon ask for (e.g. Social Security Number, Proof of Residency, Credit Card, Deposit, etc.)??
Typically no, only a valid credit card and billing address info are required. By the way, no one provider is authorized to ask for your social security number. Only the government can do that. However, a few select companies may be given an exceptional right to ask it. They are asking it just because it makes customer tracking easier. Of course, your mileage may vary given the freedom-robbing laws you have in the US.
Whatever the provider you choose, if you want to make a call from your computer, a high-speed connection is required, even in the lower tier. Don't even try on dial-up, no voice codec will sound right on a maximum of 6 kilobytes/second. Avoid high-speed, high latency access like satellite connection.
