If you didn't already know, my phone system is set up so that when someone calls any of my land lines (which include: +1 617-266-7562 [Boston, MA], +44 20 7993 2750 [London, UK], +1 585 226-1315 [Rochester, NY], plus my unlisted work phone), they all forward the call to each other as well as to my U.S. mobile phone. This way, I don't miss any calls (provided I can answer the phone!)
When visiting Europe, I used to swap the SIM card from my U.S. mobile phone into my GSM phone allowing my local Massachusetts mobile number would work there. It was a contrived, pricey pay-as-you-go scheme that cost about £1.20/minute ($2.40/min, €1.52/min) for every call (inbound or outbound.) To make matters worse, sometimes people completely unaware of the 5-8 hour time difference would call me at 2, 3, 4 or even 5 AM, and I was paying for these lovely wake-up calls!
So... rather than paying for all of these incoming calls from folks in the United States, they now have to call my European number directly if they want to reach me in the UK "on their dime." Of course, all incoming calls are free for me -- you see, in Europe, people calling a mobile phone pay a premium; therefore, I don't pay through the nose for wrong numbers or simply annoying calls from clueless people back home who have no idea I'm in Europe. Also, as it is a "real" European mobile, I am now able to send/receive text messages (my world phone never worked for texting -- Sprint couldn't tell me what was wrong or how to resolve it.) Texting is very popular in Europe and very much needed to communicate with mates.
Now when my phone in the UK rings, I know it's not some political candidate calling for a donation -- or a horny mate in New York who wants phone sex at 2:30 AM their time (7:30 AM my time!!)
So if there's something important you need to say and you're willing to pay the expense of calling an overseas mobile phone, my new European mobile number is +44 075 0590 4001. From the United States and Canada, dial 011-44-75-0590-4001. If my phone is switched off, you will be told so and will not be charged. I do not have voice mail on my UK mobile phone (what's the point?)