Cheap Mobile Phone

I recommend buying a cheap mobile phone, especially for those traveling a week or more. The prices are much lower in Europe (maybe ~20 euros, or $26 for a very basic phone) and you can get a pre-paid SIM with 10 euros of calls for use with it and then "top up" as needed.

There is a Vodaphone store at the Lisbon Airport, in Cascais (both in town and at the big shopping mall, according to the owner of our apartment) and all over Lisbon. (The other mobile-phone providers in Portugal are Optimus and TMN, which I've never heard of; Vodaphone is all over Europe.)

You want a GSM phone, with dual band (900/1800), which is what they sell there but are harder to get in the U.S.

Unlike most US mobile phones, which are tied to a particular service provider (carrier), those phones are unlocked: For other countries, you simply swap out the SIM card. You can keep it for future international travels including Festivals in England, or on return you could sell the phone in the US and probably make a profit, because those phones tend to cost more when bought here.