I just found out that I'll be heading out to Scotland for Xmas through New Year's. I currently have a locked, jailbroken iPhone with firmware 1.1.1. I've never had a reason to unlock, since I haven't been out of the country since I've had my iPhone. My question is, (really a 3 part question...):

1. If I go ahead and decide to unlock, will it have any adverse effects on any other functionality of my phone. The only reason I ask is because I see threads that go, "Since unlocking, _____ doesn't work", or all these Baseband and bootloader problems, etc. Which unlocking tool is the best to use on a firmware 1.1.1 iphone? I'll be gone 19 days, so I don't want to be out of touch that long if I don't unlock.

2. Assuming I've unlocked and I'm in Scotland, if I call overseas (to the states), or use the data features, what kind of bill should I be expecting? Which features should I avoid or turn off? (Sorry for the newb questions, don't leave the country much, 1st time with a phone that does so many different things...)

3. When I arrive in Scotland (with my unlocked phone), where should I go to purchase a SimCard (PrePaid?), and from what carrier? Do they have carriers at the Airport I can buy one from? How much to they run, and do they sell them according to Talk time or Mb's of data? Never been there, so I have no idea...

Any tips from seasoned travelers is greatly appreciated, anything to make it as smooth as possible.

Thanks for you patience,

-Berserker