Custom calling numbers for Google Voice

Question

I notice that when I use Google Voice on my iPhone (through the web interface) and I tap a number to call a contact, it asks if I want to place the call or not. However, instead of placing a call to my contact's phone number, it places it to some random number in a completely different area code. My guess is that this is one of Google's phone numbers that aren't currently in use and it knows how to handle the call I place to that number.

My questions are as follows:

1. If I call this number without using the Google Voice interface, will it always call the same contact? Will it ever change? (If so, I'm thinking I'll add a Google Voice number to each of my contacts and call this through the Phone app instead of having to launch the browser each time I want to place a call.)
2. Is there an easy way to find out what this custom number is for each contact, or is the only way to place a call to them?
3. Can the same trick be used for sending text messages to their phone number through Google Voice?

Answer 1

1 + 3. Your method should work. See here. (The comments indicate that it works for calling people too)

1. I believe that there isn't another way of figuring the numbers out.

I would note that there are some google voice native apps already back in the app store, as well as the official Google app is said to be on its way.