Trying to keep in touch with the folks back home while abroad can be difficult, if not downright expensive. However, with a little bit of knowledge (and the right kind of mobile phone), you can keep your friends and family abreast of your journeys without going broke.
For Americans traveling to Europe, you may be able to use your mobile while on vacation. While it may seem obvious, it pays to to first do a little bit of research and verify that your phone actually works overseas. Its no fun to get off the plane and realize that your lifeline to the world is cut off while you're away from home.
First, since different companies use different mobile technology standards, your choice of provider at home helps to determine whether you phone will work abroad. Take a look at your phone and see if it is a "quad-band" phone, which means that it operates on frequencies that are used in both the US and Europe. If it's not, it is worthwhile looking into getting an unlocked quad-band phone off of Ebay or MyWorldPhone.
You will still need a SIM card for both home and abroad, so when you arrive at your destination, pop into a local cell phone provider and get one. Or, you may want to wait to get your phone abroad, since they almost certainly have the latest options. You can even bring it home and use it with a compatible service like T-Mobile or AT&T.