Nicosia City Centre is generally easy to explore on foot and, given that the conference venue and most of the hotels are within the walled city, you may not need any other means of transportation during the conference. However, if you like to explore Cyprus more, here is some information on the available transportation options.
Shuttle services to and from the airport
Kapnos Airport Shuttle: https://www.kapnosairportshuttle.com/
Bus
OSEL is the official bus organisation of Nicosia district. On their website you can find information on routes and tickets (http://www.osel.com.cy/).
Cyprus by Bus is a useful site for planning your bus journey (http://www.cyprusbybus.com/)
Intercity Buses will easily get you from one city centre to the other and a day ticket costs €7.
For timetables and destinations visit: http://www.intercity-buses.com/.
Taxis in Nicosia
Millenium Taxis: + 357 22813813
Finlandia Taxi Service: + 357 22666000
Rental Cars
If you are interested in renting a car, here is a directory of car rental companies in Cyprus:
http://www.cypruscarrental.com/