"... So, I just wanted to know if there is a way to choose which region iDVD burns for. That's it. It is for personal use and not for broadcast. ..."
I realise it's not for broadcast, as in you're not giving it to a TV station. However, the television, VCR, TV tuners, DVD players, etc. all accept a certain type of signal only. These signal formats were defined with over-the-air broadcast in mind, thus the term "broadcast format". Today we have new broadcast formats defined, such as HDTV. For the record, PAL at 625 lines/25 frames is a higher quality format than NTSC (540 lines at 30 fps*).
Because MPEG-2 is a digital data format, the translation to each nation's format is relatively easy (videotape would require a hardware converter).
However, be careful of image stretching horizontally or vertically. NTSC DV is 720x480 pixels while PAL is 720x576 and SECAM [Sequential couleur avec mmoire] is 833x?. Also, your audio tracks will speed up or slow down, due to the audio sync to video at different frame rates/second. Not critical for voice embedded on the camcorder but don't add music effects (soundtracks) until after your convert.
You must use the broadcast format to play the DVD on a given DVD player. If it will be used only on a computer, you might be OK. I would try to contact them if you are unsure how they want to view the DVD (computer or TV screen), to avoid what comes next:
Apple recommends PAL for SECAM nations, because SECAM is a transmission standard but not a production standard. It's common for retailers to offer PAL/SECAM multiformat recorders/players in these countries.** You can export either NTSC or PAL via iMovie. To do so, you must export your NTSC DV from iMovie as a DV stream (many hours and giagabytes later) you can import the DV stream in PAL format (new project), save and burn.
iMovie exports Region 0 (anywhere) while iDVD allows the option of embedding a specific region if desired.
The different formats are a result of power generation formats adopted early in the last century; a nation with 50 Hz AC will typically be PAL (2 pulses of AC power per frame) while in Canada we have always had 60Hz current, hence the 30 fps standard. A math formula (how much signal can fly over an airwave per second) results in the different pixel counts at different frame rates, apply the formula and they both result in the same amount of data/second. As for SECAM, well they're French. It differs in that it stores color information briefly before combining it with the other signals. Eastern Europe propably adopted it due to the nature of Soviet policies at the time, whereby the USSR would purchase "turn-key" factories from western companies. Ever notice how a Lada resembles a 1974 Fiat 124?
* Its technically 29.97, or 1 frame per thousand less than 30fps.
** In other words, I was wrong when I assumed a SECAM format for DVD existed.