I don't know the layout of the 2.4, but with the 1.9 it was fairly easy.
There is a little gap at the bottom of the connector which will take a small screwdiver, you may have to twist the connector around a bit to find it. Just ease this up with the screwdriver while pulling and supporting the top part with your other hand. I got home from work, squirted WD40 around the bottom to ease the thread and waited for 4 hours. Came out fairly easily with a long 9mm socket.
Used copper grease on the thread of the new one and all OK. I only had one to change, but now I know what to do, reckon I could change all of them in an hour (+ waiting for the WD40 to do it's work).
Believe the 2.4 takes 5 glow plugs, but if you can get a meter and check the resistance then you probably won't have them all gone.