If you're an English speaker coming to Rome and looking for work, teaching English as a foreign language is an obvious choice. English is still a vital international language, and the city is full of willing students. On the other hand, it's also full of English speakers who could use the extra money themselves, so be prepared for competition.
There are two main methods of teaching English in Rome: giving private lessons, or teaching classes through a school. Which works best for you depends at least partly on your temperament. (You can also do a mixture of both, though some schools have rules on their teachers giving private lessons on the side.) The various pros and cons of each method are covered below, along with information on the CELTA qualification.
Teaching English privately
Many teachers around Rome take private students for English lessons or conversation practice. If you'd like to join them, your two main challenges will be finding students and keeping them.
To find students, try advertising on the various Roman classified sites like Porta Portese, and Wanted in Rome (the former may be more frequented by Italians), or put up adverts around the universities. Word of mouth is a powerful tool, especially in Italy, so ask people to recommend you to their friends.
As far as keeping students goes, when you're giving one-to-one lessons, you're more likely to have casual students who are taking English lessons on a whim: they'll often cancel at the last minute, or forget about the classes altogether, leaving you standing in the street pressing the doorbell in vain. It's best to be firm about your cancellation policy right from the start, because it can be hard to bring the subject up once you've established a relationship with your students. Ultimately, though, flakey students are a fact of life for English teachers, especially in the summer, so it's worth planning your living budget with a few missed lessons in mind.
If all that sounds a bit much for you, consider teaching English in a school instead...
Teaching in a language school
There are plenty of English language schools around Rome: you'll see their advertisements on billboards and public transport wherever you go. Some of them are good to work for and some aren't, so it's worth asking around (or doing some Googling) before you commit yourself. Make sure you double-check any contract you sign, and that you are quite clear on how much you get paid and also when you will get paid. Just in case the worst comes to the worst, always have a plan B lined up.
You'll find some of the language schools advertising for staff on sites like Wanted in Rome, but it's worth talking to people who have tried teaching English in Rome themselves. Dave's ESL Cafe is a very useful site for English teachers in general, and their forum includes a section for people teaching in Italy.
Qualifications and the CELTA certificate
If you're seriously interested in teaching English, then you should consider getting a teaching qualification. TEFL (Teaching English as a Foreign Language) certificates can vary enormously in quality, but the CELTA is an internationally recognised qualification.
The other advantage of a good qualification is that it usually comes at the end of a good course on how to teach English; while the piece of paper may help you get your first job or student, it's your ability as a teacher that will get you those all-important word-of-mouth referrals.
The CELTA (Certificate in Teaching English to Speakers of Other Languages) is run by Cambridge University, and it will certainly help you to get the better jobs in the industry: if you want to teach in a school and avoid some of the shadier outfits, you'll definitely find a CELTA useful.
Typically it takes a month of full-time study to get a CELTA, although part-time versions lasting three months or more are available. Courses are run all over the world, including Italy, so there's no need to put off your trip if you can afford to support yourself while you study: learning "on the ground" may also help you make contacts for when it comes to finding a job. The CELTA course in Rome is run by International House.