Install mingw
  + download and run mingw-get-inst-20101030
  + install options
    - C Compiler
    - C++ Compiler
    - MSYS Basic System
    - MinGW Developer Toolkit
    - MSYS System Builder
    Using pre-packaged repository catalogues (20101030)

Launch Msys shell
==================================
mkdir rtems-work
cd rtems-work
cvs -d :pserver:anonymous@www.rtems.org:/usr1/CVS login
cvs -z9 -d :pserver:anonymous@www.rtems.org:/usr1/CVS co -P -r rtems-4-10-branch rtems

Download and install the following
==================================
From: http://www.rtems.org/ftp/pub/rtems/mingw32/4.10/
  rtems-4.10-autoconf-2.68-1.tar.bz2
  rtems-4.10-automake-1.11.1-2.tar.bz2
  rtems-4.10-i386-rtems4.10-binutils-2.20.1-3.tar.bz2
  rtems-4.10-i386-rtems4.10-gcc-4.4.5-2.tar.bz2
  rtems-4.10-i386-rtems4.10-gcc-c++-4.4.5-2.tar.bz2
  rtems-4.10-i386-rtems4.10-gcc-libgcc-4.4.5-2.tar.bz2
  rtems-4.10-i386-rtems4.10-gcc-libstdc++-4.4.5-2.tar.bz2
  rtems-4.10-i386-rtems4.10-gdb-7.1-2.tar.bz2
  rtems-4.10-i386-rtems4.10-newlib-1.18.0-17.tar.bz2

I used this script to do the untar.  It was in the directory with
the tarballs.

#! /bin/bash

BASE=`pwd`
cd /
for f in ${BASE}/*.tar.bz2
do
  tar xjf $f
done

Bootstrap RTEMS
===============
export PATH=/opt/rtems-4.10/bin:$PATH
cd ~/rtems-work/rtems
type autoconf
# verify in /opt/rtems-4.10/bin
type automake
# verify in /opt/rtems-4.10/bin
./bootstrap
# This took about 30 minutes on my home laptop

Build RTEMS
===========
cd ..
mkdir b-pc386
cd b-pc386
../rtems/configure --target=i386-rtems4.10 --enable-rtemsbsp=pc686 \
  --enable-tests=samples
# about 2-3 minutes
make