GNU Embedded Libraries
http://sourceforge.net/projects/gel/
Sources of GEL.

GNU Development Chain for 68HC11 and 68HC12.
http://m68hc11.serveftp.org
http://m68hc12.serveftp.org
http://www.gnu-m68hc11.org
The main site to obtain the GNU tools for 68HC11 and 68HC12. This site provides binaries of the compiler for GNU/Linux and Windows. Latest development and patches for the GNU HC11/HC12 Tool Chain is also available on that site. These tools are integrated in FSF sources (gcc, gdb, binutils) since July 2000.

GNU Compiler Collection
http://gcc.gnu.org
FSF Official distribution of gcc. It includes the 68HC11 and 68HC12 port.

GNU Debugger/Binutils and others
http://sourceware.cygnus.com
You'll find here the debugger GDB, the linker/assembler and other tools. They have been ported to 68HC11 and 68HC12.