Italy is a popular destination for TEFL teachers and English teachers are always in demand. The climate, the food and history make it attractive to many English teachers. The number of language schools in Italy has grown steadily over the last decade and it is increasingly rare to see a job advertisment of any kind that doesn't require applicants to have a fair level of English. This means that even if you can't find work with a school, there is always private work available.
You won't get rich!
This applies in almost every country if you're a TEFL teacher, but Italy is not a cheap place to live and the salaries are some of the lowest on offer in Europe. It isn't too expensive to rent an apartment in the south, but the money, and most of the work, is in the north where prices can be much higher. Added to that, gas, electricity, fuel and insurance costs are the highest in Europe.
Working for a school
Despite the headline advertising, many schools employ native speakers without ESL certification provided they 'feel' right. This is partly because unqualified teachers are cheaper than qualified teachers. Language schools pay anywhere between 900 and 1500 euros a month for a 'full-time' teacher. However, contracts are almost without exception short-term 9-10 month contracts which do not include sick or holiday pay entitlements. Teachers are very rarely paid a flat-rate salary and are instead paid only for the actual hours they work each week.
There is a lot of demand for private teachers, particularly in the north. This applies not just to private individuals who want lessons but also companies who are seeking to reduce their training costs. Many teachers are able to find placements working inside a client company. Prices are very open, with teachers charging anywhere from 15 to 40 euros an hour.
A quick google search will uncover hundreds, maybe thousands of language schools across the country. One of the best ways of finding a job is to email schools directly, but many advertise locally. Almost every school closes during August, but the annual holiday period can extend from mid-July until mid-September. New teachers are usually taken on either in September or January.
EU nationals don't need a visa to live or work in Italy, though you must register as resident within 3 months of arriving. Non-EU nationals will find it very difficult to obtain a work visa for teaching. In these cases, apply for a visa from your own country, to save time, headaches and immense frustration.