The SDCC home page at http://sdcc.sourceforge.net/ is a great place to find distribution sets. You can also find links to the user mailing lists that offer help or discuss SDCC with other SDCC users. Web links to other SDCC related sites can also be found here. This document can be found in the DOC directory of the source package as a text or HTML file. A pdf version of this document is available at http://sdcc.sourceforge.net/doc/sdccman.pdf. Some of the other tools (simulator and assembler) included with SDCC contain their own documentation and can be found in the source distribution. If you want the latest unreleased software, the complete source package is available directly from Subversion on https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc.