I have an Airport Extreme card in my iBook and I would like to hook up a better antenna to get further wireless range. Do you know if the connector on the card is MCX type?
Yes, you are correct. MCX is the correct connector and an MCX to N Male pigtail will work fine. The N Male connector will connect up to most standard external antennas.
If you need a longer cable run, you can also purchase a Low Loss 400 jumper cable with an N Male connector on one end and an N Female connector on the other: