Can I use my California interim (temporary) driver's license outside
of the country while I wait for my actual license to arrive? I will be
visiting Switzerland and would like to drive.

For driving abroad, you need to obtain an International Driving Permit (IDP). 
http://travel.state.gov/travel/tips/safety/safety_1179.html#driving

To apply for an international driving permit, you must be at least age
18, and you will need to present two passport-size photographs and
your valid U.S. license. The cost of an international driving permit
from these U.S. State Department authorized organizations is under
$20.00.

http://travel.state.gov/travel/tips/safety/safety_1179.html#permits

So, the answer to your question is that you cannot drive with a
temporary license outside the country.

Sorry, dumbguru-ga, but this is not true in some European countries. 
Just as I can drive in the States with my German driver's license,
holders of US licenses can drive here  - not permanently, but for a
vacation.

zo0m-ga, you need to contact the Swiss consulate in SF
Swiss Consulate General: 456 Montgomery St., San Francisco (415) 788-2272 
and ask them:  a) about driving with Cal license
               b) about using a temporary license.
And then consider that you might want to drive to France or Germany or ...

AND, if you are planning to rent a car, or drive a car rented by someone else,
the rental company should be asked:  about the license, and about its age policy.

myoarin-ga If they let him drive with his temporary license, I will
personally mail you a hundred dollar cheque.

jeez! It's illegal to even drive on the highway with a temp license
forget a foreign country!!

Thanks for the answer myoarin, I will most certainly contact them.

Dumbguru, are you serious about not being allowed to drive on highways
with a temporary license?

Dumbguru-ga,
I won't bet with you, 'cause I expect you're right, but if the temp
license has a photo, maybe she/he could.  For a while, German kids
that went to USA and got a driver's license, could use it here, even
though they were not yet 18 yo as required by law for a German
license, and then get that when they were old enough.
The law was changed, maybe by lobbying from the driving school
industry; it could be cheaper to go to the States and get a license
that go through driving school here.
Anyway, I didn't want to step on your toes, but a flat statement that
one needs an Intl license could misinform other readers.
Okay?  Drive safely  :-)

myoarin-ga!

I was just messing with u.. you must be one of those researchers.. i
like to mess up with their heads.. its fun... but zo0m-ga im serious
about the highway, its a major offense.

dumbguru-ga, and I was already thinking about taking on your bet after all...
   NO problem, all in the friendly pursuit of truth.
Actually my dad when he was 98 got his Cal licensed renewed, after a
couple of nice blokes visited him and heard his agreement just to
drive around town, a small place with no buses or taxis.

Where can one drive with an interim license?  Seems like it would be
just as valid as the plastic one that was being made.

my local DMV has no idea either.. 

and dumbguru, i can't find anything about not being able to drive on
the highway with the interim license.. to my knowledge it's the exact
same thing!

"Driving in Switzerland
You may drive in Switzerland with your valid U.S. license for up to
one year after your arrival; then you must obtain a Swiss permit.
Swiss licenses are only issued on the basis of valid U.S. licenses.
Holders of expired U.S. licenses must take the Swiss driving test when
applying for a Swiss license. The minimum age for driving or learning
to drive is 18. Liability insurance on motor vehicles is compulsory in
Switzerland and must be provided by a Swiss insurance company."
http://bern.usembassy.gov/general_information.html

In order to answer your question it would probably be helpful to know
why you currently have a "interim (temporary) driver's license".

"Driver License Information":
http://www.dmv.ca.gov/dl/dl.htm

Thanks for the comment! 

I have a temporary license because I'm waiting for my real license to
arrive. I just recently started driving and I am over 18.