I don't have any special programs to side load apps. As emusan said, you can copy the .apk file over to the PE (by any means... usb connect to computer, flash drive, SD card). I typically just email myself the file, and when I double click on the attached file inside the email, it automatically installs (or at least asks me if I want to). No moving files around, no needing to navigate through a file explorer. It may not be elegant, but it works!
