To get all your sims out of there, open up your cheats (ctrl-shift-c) window, type in:
testingcheatsenabled true
then open the cheat window back up (ctrl-shift-c) and type:
resetsim *
This will reset everyone in town. Please note that your game may lag for a minute or two as it resets everyone.
You could also go into edit town and pick up the lot and then place it back down, this will set everyone onto the sidewalks. But they may still be stuck there so if they are you will need to reset them all.
I would go in and edit the lot you are having issues with so that people won't get stuck (remove the air conditioner), so that it doesn't happen again.
