I'm going to a conference in Aix and flying in to Marseilles. I want to take the bus from the airport to the city. Where in the city is the bus station that I will use? How close is it to the Rotonde?

Thanks for all your help!

Let's be clear. The airport is well outside the city of Marseille. There is an airport bus to Aix. There is a shuttle to Marseille. If you are going to Aix it will be worth half of your day in hell to commute via Marseille. And Rotonde, as a name, exists in so many places that it made my head spin. I assume you don't mean the University of Ottawa, for example (good school, though.)
If you could do a little work and be more specific, you might get some good advice.

http://www.marseille.aeroport.fr/fra.../acces_bus.jsp

Taking a guess...perhaps by the use of "city" the OP means Aix.

Rotonde in Aix, again another guess.

Here's some information that should answer your question.

http://www.provencelive.com/practica...toaix.html#bus

The buses, called "Navettes", are easy to find at the airport. There is a regular shuttle to Aix, maybe every half hour during the day.

They take you to the gare routiere (bus station) on the Avenue de l'Europe in Aix.

If you are staying at the Hotel Rotonde, it is about half a block from the bus station on the Avenue des Belges, just past the traffic circle (rotonde). This hotel is a few blocks from the Place Charles de Gaulle, where the more picturesque parts of Aix begin.