My '93 SL1 (automatic) with 150k miles recently started making a
high-pitched and loud squealing that seems to come from the front of
the car at the drivers side, but it's hard to be sure.  So far it only
makes the sound when the car is cold, immediately after starting to
drive, and especially when cornering with load placed on the drivers
side (i.e. left turns).  It seems to be getting a bit worse each day,
but it's also been getting colder.

I could only find one thread where several people said they had exactly
this problem, but no one was able to get a shop to diagnose it
(especially since you'd have to drive it to the shop and by then it
wouldn't make the noise anymore, you'd have to let it sit overnight).

The front brake pads are near their end, could this be the wear sensor
or does that sound when NOT braking (I've never heard one before so
don't know what to expect)?  Or could it be the suspension, engine
mounts, or even a belt?  Just want to make sure it's nothing
immediately seriously, because I wanted to take the car on a trip 3
hours away this weekend.  

Thanks for any suggestions.