Communicating to the world is easy while in Lithuania as the country's internet and cell phone facilities are among the world's best.
The expansion of the internet has been especially massive. So much so that Lithuania now firmly holds the 1st place in Europe according to high-speed internet users as the percentage of total population. With nearly every city dweller having internet at home internet cafes became rare. PCs are available at some libraries, however. Wireless internet (Wifi) access is possible (free) in the major shopping malls, libraries, restaurants and hotels (ask in advance). A few streets and squares in the main cities and resorts have free municipal wireless internet coverage.
Moreover, nearly every location in Lithuania is covered by a 3G GSM cellphone network. Roaming charges are significant but fierce GSM network competition ensures that for local clients the charges are the lowest in Europe. A foreigner may easily buy a cheap pre-paid SIM card such as "Ežys", "Pildyk" or "Labas" and thus pay the negligible local rates. These are sold at every kiosk and at specialized provider shops at the malls. At the latter, one may inquire about the specific plans depending on your needs (international calls/internet/local calls/SMS). The subscription plans (paid for monthly) are useful only for residents.
Some public payphones still exist in cities (as required by law) but barely anybody uses them today. Payphone cards may be acquired at kiosks.
An international phone prefix for Lithuania is +370. When calling from another Lithuanian phone it is replaced by 8. This is followed by either a city prefix or a cell phone provider prefix (1-3 digits) and then the number itself (5-7 digits). The prefix(es) may be missing from phone number listings.
If you prefer sending postcards the old way post offices are now available at many of the largest shopping malls (open 7 days a week until late evenings). The traditional post office locations at the ground floors of some residentials have been recently downsized and may be hard to find as they are not well-advertised - ask a local to show them and hope that the office will be open (unlike in the malls the opening times are limited to working week). Stamps, envelopes, and some postcards are sold at the post offices.