Some or all of the following means of communication will be necessary for your everyday life in Italy. This is a brief overview:

Post
Post office opening hours are normally 0830-1900 Monday-Friday, 0830-1300 Saturdays.

Postage stamps can be purchased at tabaccheria (tobacconists) or post offices. However, sending letters from the post office means you can check the postage is sufficient. If it is not, airmail will be sent by surface mail! Added March 2007 by Max:
Preferred way of sending mail is 'Posta Prioritaria' (priority mail), priced at 0.60EUR for normal sized letters up to 20g. If the destination is abroad the delivery will be by air mail. Normal mail is cheaper and takes a bit more to be delivered. The Post is quite reliable and more efficient than in the past. You shouldn't need to enter the yellow post offices. Mail boxes are red.

Many Italians pay bills using the Conto Corrente (giro credit) payment slip at post offices, causing long queues.

Added March 2007 by Max:
Queues are mostly caused by unflexibility of employee duties. Don't be shocked if you see one employee with a very long queue and a second one with the 'closed' sign sitting nearby.

Television
Television set owners must pay the 'Canone d'Abbonamento' tax, costing about 100 Euro yearly.

The television system in Italy works with the PAL standard. The state-owned Italian Broadcasting Company RAI owns 3 channels (RAI Uno/Due/Tre), broadcasting in Italian, along with many private channels.

To see foreign-language programmes you will need a satellite dish ('Antenna Parabolica'). There are many free satellite channels - a digital decoder can access even more (for example, Sky News and CNN)

Telephone
The main telephone service provider is Telecom Italia, though telephone services were de-regulated several years ago so other companies (including Albacom/Tele 2/Tiscali/Infostrada) are available. Telecom Italia will provide your phone line and telephone directories, plus handsets and units ('Scatti') to rent or buy.

To apply for connection, simply dial 187. Non-EU citizens will find the process more involved, as they must send a written application by registered mail ('Raccomandata') - with photocopies of documents and payment.

Telephone billing is every 2 months - pay at the post office or through your bank.

Internet
When in Italy, check that your computer is set to 220-230 volts. Voltage can vary, particularly in the south, so find out what the local supply is and adjust your computer accordingly.

To find an Internet Service Provider (ISP) in Italy, try searching online for any of the following companies: Tin.it, Virgilio, Libero, Infostrada, Italian Online (IOL), Jumpy, Wind. Somewhat oversubscribed, these can be a little slow in connecting, but are vastly improved on a few years ago. Italy's internet revolution has now really taken hold, despite a slow start.

Signing up online is in Italian (!) but a lot of the terms are guessable - look for 'abbonato' meaning 'sign up'. You will need your codice fiscale to sign up. Some ISPs offer a broadband service, including some of the telephone companies, who may offer existing customers tie-in deals.

Submitted 29/7/07 by David:

"It is a pity you can't find an Italian ISP that supports English on it's web pages to make things a bit easier for the large number of potential non Italian speaking customers. I used Tiscali but trying to cancel them is a nightmare! I only had dial up access using my own modem. I joined a plan that cost around 15 Euro/month and allowed "free" access to the net between 6am and 6pm. After 16 months I decided to cancel the service but was told I could only do this 60 days before the anniversary of joining. This is quite unlike the UK where most ISP's will allow cancellation at any time, after the first year of the contract, provided they are given a months notice. Tiscali will not accept notice of cancellation prior to the 60 day period or after the anniversary date. So if you miss the 60 day window they continue charging and lock you in to the contract for a further year. I am not sure if this contract lock in is unique to Tiscali but suspect this rather unscrupulous practice might be common. It highlights the difficulty of signing up to a contract written in a language that one does not understand."