I am frequently asked for my opinions regarding the Arabic school that I have attended in Fez, Morocco. The Arabic Language Institute of Fez ("Alif" as it is affectionately known) is housed in the Centre Americain, a large villa with a lovely English language bookstore and coffee stand in its courtyard.
The center is run by David Amster, a classicist by training. I believe he took out college loans while a university student and used the money to buy Greek vases at one of the auction houses. He assures me that he has long since paid back the loans and it was "well worth it." Amster's commitment to the preservation of the historic old city of Fez (or "medina") is truly legendary. He once drove to Casablanca to rescue two old wooden doors that had been poached from a riad house in Fez, and returned them to their owner. David is delightful, informative and full of advice and wisdom about life in Morocco.
I think ALIF is one of the best places to study Arabic in North Africa, both because of price and quality of instruction. Many of the Arabic teachers there also work for the local university and many have advanced degrees. They also have worked for years with American students which has taught most of them that Americans are accustomed to a particular pedagogy when it comes to learning language, and it is not the memorize-regurgitate-repeat of the French system.
The school is organized around six week modules. Their schedule is available here. Students can take three week or six week sessions in both Modern Standard Arabic (MSA) and Moroccan dialect or darija. The school abbreviates this dialect as "CMA" for Colloquial Moroccan Arabic. It's my sense that the curriculum is more standardized for the six week MSA sessions. The three week sessions are more variable and the students have more say in what is taught in those courses.
Nevertheless, the quality of instruction there varies by instructor. I think Zaim is an excellent professor for beginning students, and he will have you speaking in case endings by the end of your first six week session. Hamid is a great teacher if you are interested in politics. He is a true political junkie. He was horrified the morning after Obama's State of the Union speech to learn that I, a political scientist, had not stayed up to watch the address at 3am like he had. He has also read virtually every piece of literature available to him in either English, French, Spanish or Arabic so he can be really helpful to those interested in literature studies.
It is better for graduate students looking for serious language study to take classes there during the school year, rather than during the summer. During summer months the Center can be overrun by American undergraduates studying abroad with the intentions of normal American undergraduates. In the fall the center is full of Fulbrighters, so those who intend to do research can meet a community of other young scholars by studying at the center.
It's important to note that dialect on the street, CMA, is very different from MSA. I recommend anyone traveling to Morocco for the first time to take either the three week intro to CMA class, or to take private instruction in CMA for at least two weeks prior to beginning MSA. It will lubricate all of your social interactions during your entire stay if you can communicate people on the street: every taxi driver, restaurant owner or waiter, not to mention your Moroccan friends will appreciate your grasp of even a few words of dialect.
Speaking of your Moroccan friends, I also highly recommend that during your first stay in the country that you live with a host family. Moroccan hospitality is truly legendary and you will learn a million small details about daily life in the presence of a family than in a dorm or apartment. I recommend living in the Old City and requesting a family that speaks no French or English and has small children in the home. They will teach you more words than any adult companion.