Scheme is a dialect of Lisp, which differs from traditional Lisp dialects so much that it is considered a separate language with its own name.
One of the popular sites devoted to Scheme is http://www.schemers.org
Recently, new standard of Scheme, r6rs, has been ratified (see RevisedSixReportOnScheme). Before this, r5rs (RevisedFiveReportOnScheme) was the actual standard.
InteLib supports a non-standard (yet?) dialect of Scheme, named InteLibScheme.
A good text devoted to Scheme macro system: http://petrofsky.org/src/primer.txt