The highlevel macro system described in r5rs is often referred to as SYNTAX-RULES. Although this is the only standardized macro system for Scheme, others are in common use:
Syntax-rules macros maintain hygiene automatically, are referentially transparent (see referential-transparency?), and provide a simple pattern-matching? language.
There is not too much introductory material on this macro system. Other than the r5rs itself, try this nice tutorial: JRM's Syntax-rules Primer for the Merely Eccentric or ask on #scheme.