I did a quick search and found this site helpful. .sit is a compressed file (like a zip) usually done by StuffIt for mac, but there are DOS/WIN versions you can download from this site too. Hope this helps.
<A href="http://helpdesk.uvic.ca/how-to/exchange/internet/coding/sit.html">http://helpdesk.uvic.ca/how-to/excha...oding/sit.html</A>