windows:
linux:
1. 下载ruby 1.8.6
a. http://rubyforge.org/projects/ruby/
b. tar -jxvf ruby-1.8.6.tar.bz2
c. ./configure;make;make install
2. 安装 rubygems-0.9.2.tgz
a. http://rubyforge.org/projects/rubygems/
b. tar zxvf rubygems-0.9.2.tgz
c. cd rubygems-0.9.2
ruby setup.rb
3. 挨个下载rail套件(only gem)
从http://rubyforge.org逐个下载Rails框架所需的各个安装包，这种方法比较麻烦，但是能够保证安装成功。
需要下载的安装如下
a.activesupport-1.4.2（下载地址http://rubyforge.org/projects/activesupport）
b.activerecord-1.15.3（下载地址http://rubyforge.org/projects/activerecord/）
c.actionpack-1.13.3（下载地址http://rubyforge.org/projects/actionpack/）
d.actionmailer-1.3.3（下载地址http://rubyforge.org/projects/actionmailer/）
e.actionwebservice-1.2.3（包下载地址http://rubyforge.org/projects/aws）
f.rail-1.2.3 (http://rubyforge.org/projects/rails/)
4. 按顺序install以上gem
gem install activesupport-1.4.2.gem
gem install activerecord-1.15.3.gem
gem install actionpack-1.13.3.gem
gem install actionmailer-1.3.3.gem
gem install actionwebservice-1.2.3.gem
gem install rails-1.2.3.gem