Instructions:

1. (Windows only) Download Strawberry Perl and install it on the machine you want to do your checking in from. Be sure to get the right version for your system (32-bit or 64-bit).
2. Download the FourSquare Checkin zip file and extract it somewhere. The extracted foursquare.cfg file in this directory is empty except for some comments.
3. Copy the contents of the text box below, and paste it into the foursquare.cfg file.
4. Fiddle around with settings as you see fit.

Note that after installing Strawberry Perl, you should just be able to double-click on foursquare.pl to run the script. If you run it from the command-line, however, you can specify which venue to start with (by number). The script will stop when it finishes checking into the last venue in the list, regardless of which one you start with, so use the option venue-number parameter when you need to pick up where you left off after a crash, reboot, etc.