What is a SIT file and how do i place or open it in logic

.sit files are kind of like .zip files in the way that they are compressed data. You need stuffit expander, which I think comes with every Mac to open them, and then the original file will be placed on your desktop, or wherever you tell it to.

or

http://www.versiontracker.com/dyn/moreinfo/macosx/182&vid=274856&mode=info

I'm pretty sure that my PB came with it pre-installed...
Indeed, I'm certain as I did a complete wipe and reinstall and I still have it...