Approaches and Landings

Folks,

I am new to FS world. I've been reading lot of books/help to understand how to navigate etc. But I've not seen a place that would answer my question in a nut shell. Here is my question

When I use my GPS for navigation, it plots a straight "purple" line on the map and all that you got to do is navigate. However, as you approach the destination, you would be diving into the airport if you followd the GPS purple line. I've been selecting different approches and vectors using the GPS. They draw thin dotted line in the map depending upon which Vector I choose. Now here is the question,

1) When and How do I deviate of my main course towards the final approach Vector?

2) Is there a formula to calculate what should be the height at a given distance from the ILS approach? Most of the times when I go around the Vector (curves), by the time I reach the ILS zone, I am too high always. How do I maintain the height even when I curve? Please assume I am flying a 747

3) I am very bored with "Soar airlines" , "Orbits" and "transworld". I see beautiful of screenshots of lot of commercial airlines (like american etc)...Can anyone provide me a link to one that also has a Virtual Cockpit? Most of them I tried does not have Virtual Cockpit

Thank you for your replies in advance