Does it cost money to use imessage with someone in a different country?

I live in the USA and my friend lives in Canada. She just got an iphone and i have one as well so i was wondering if it would cost extra money to use imessage considering she's in a different country or would i be free of extra charges? I understand that I would be charged extra if it was via text but does the same thing apply for imessage?

IPhone 4s Flash blows out photos? - 2

I just got an iPhone 4s and whenever I use the flash on the camera it makes the one side of the image really bright (probably because it's positioned right beside the lens). Anyone have any ideas on why this is happening or how to fix it?

Added (1). Turns out there was a plastic protector under my case I didn't peel off that was diluting the flash

IPhone 4s Flash blows out photos?

I just got an iPhone 4s and whenever I use the flash on the camera it makes the one side of the image really bright (probably because it's positioned right beside the lens). Anyone have any ideas on why this is happening or how to fix it?

Added (1). Turns out it was protector

Sprint Iphone 4 goes from 5 bars to No service and Searching?

I called sprint and they tried everything on their end and told me to reset the network settings, even resetting the entire phone, and nothing helped. I read somewhere that the antenna is touchy on these phones and wearing a case may help? I would like to hear any fixes and if anyone else has had these issues. It worked completely fine the first day I had it and then it just started losing service for no reason.

What's the extra charge for using iTunes?

Everytime I buy an app from the app store from my iPhone, I get charged the 'app' charge and then on my statement I could get charged anything between 6-8 euros described as a 'finance purchase charge'
What in earth is this?
Every app I buy is costing tons extra. Has anyone else experienced this?
I'm living in Ireland, and use AIB Visa card.
Thanks for your help.

Added (1). I should add that this is nothing to do with interest charged or the card being overdrawn.
For example. If I had a credit card that was zero on the 1st of the month why would there be a charge of 6-8 euros each time I use the app store through the month?

Why won't iMessage work even when I connected to the Internet?

I have an iPhone 4 and iMessage works with ever other person that I have on my contacts with an iPhone but not with this just one person. It goes off an on but lately it's been off most of the time even though we're both connected to the Internet. Someone help