Film is generally shot and projected at 24 frames per second (fps), so when film frames are converted to NTSC video, the rate must be modified to play at 29.97 fps. During the telecine process, twelve (12) fields are added to each 24 frames of film (12 fields = 6 frames) so the same images that made up 24 frames of film then comprise 30 frames of video.Video plays at a speed of 29.97 fps so the film actually runs at 23.976 fps when transferred to video.

AVID does a 2-3 pulldown (which is used in a lot of film editing)

But most other editors use 3-2 pulldown.

2-3 Pulldown vs. 3-2
It is commonly referred to as 3-2 pulldown; while modern telecine machines can go either way. Therefore, AA BB BC CD DD. If the telecine is set for 3-2, you'll get BB BC CD DD AA.

Another slightly confusing consideration: When the pulldown process occurs, it turns out that the video version of the film runs slightly SLOWER than the original film did. This occurs because the film is running at 24 frames per second, but in order to create the right pattern of A-B-C-D on the video tape, which runs at 29.97 frames per second, the film was actually played at 23.976 fps during the telecine (film->tape process).