It took me some time, but I found it, though. Here is the XBasic page itself:

http://www.maxreason.com/software/xbasic/xbasic.html

The URL to Max Reason's web site was

http://www.maxreason.com

Sorry, I thought it was .net -- XBasic plus the documentation is a little over 5 MB, but at the XBasic site, you can get an idea of what the whole thing is about before you actually spend time downloading it.