You can take the 66 or 67A bus from Wood Quay, Dublin City Centre. Buses depart between two and four times per hour, depending on the time of day. From the city centre, the fare to Maynooth is Euro 1.65.
The 66X and 67X buses are faster, but much less frequent, generally only operating during rush-hour. From the city centre, the fare to Maynooth on one of the X-buses costs about Euro 2.85. There is also the 67N, a "Nitelink" bus (that is, an after-midnight service) that travels to Maynooth every day except Sunday. The fare is Euro 6.00.
If you're going to be staying in Dublin and travelling to Maynooth for the conference, you might wish to avail of the "7-Day Dublin Rambler" ticket. This costs Euro 18.00 and valid on all Dublin buses and the Airlink.
Trains for Maynooth depart from Connolly Station, Dublin City Centre. The journey shouldn't take longer than forty minutes.
The last train leaves for Maynooth at about 22:30 Monday to Saturday, 18:20 on Sundays.
The Aerlink bus (number 747 or 748) goes directly into the city centre, from where you can then take a bus or train as above to Maynooth. The journey costs Euro 5.00, and during the day the buses depart every ten minutes.
Hiring a Maynooth-based taxi (see the list below) will usually work out cheaper than taking one of the taxis that wait outside the airport's arrivals terminal, though of course you will have to wait for the taxi to come from Maynooth. However, you can book the taxi in advance so that it will be waiting for you when you arrive. Fares are typically Euro 50-55.
Express Cabs
(+353 1) 628 9866 do on-line booking.
Major Minor Cabs (+353 1) 601 6160
Maynooth Cabs
(+353 1) 628 9999
MCL Cabs (+353 1) 628 6539
GF Cabs (+353 1) 6016160
Leixlip Cabs (+353 1) 6286539.
Citylink and Nestorlink run regular express coaches from Dublin Airport to Galway. Neither stop in Maynooth. However, if you get off at the Liffey Valley or Spa Hotel stops, you can travel onward to Maynooth via Dublin Bus (number 66 or 67).