参考以下这篇文章来建立Windows XP host和Windows 2k3 guest之间的桥接.以便做网络试验
在Windows XP下用VirtualBox安装Ubuntu 8.04后，默认的是NAT连接方式，不需要做任何更改就可以上网，但是这种方式很不灵活，你无法像访问局域网中的其他主机一样访问Linux，为此，可以建立桥接，让你的Windows XP和Linux在网络中具有同等的地位。
具体方式步骤如下：(下面是在Ubuntu论坛上的文章设置方法)
The installation of VBox, creation of the guest and installation of Debian Etch was done in the normal fashion. Once that was completed I followed the following steps to setup networking.
以正常方式完成VBox的安装，Guest系统的创建以及Debian的安装之后，按照以下步骤来设置网络
I. Create Network Connection in VBox
1. Network;à SettingsàOpen VBox??
2. Click on “Attached to” and then select “Host Interfaces”;
3. In Host Interfaces click Add;
4. Type "VirtualBox Host Interface #" without the quotation marks where the # represents a number for the interface, usually 1 (on one computer the name of the virtual box host interface appeared automatically, on the other computer I had to type the information);
5. Click OK, and
6. Close VBox
在虚拟机中创建网络连接
1. 虚拟主机设置 -〉网络 –〉网络连接方式
2. 选择“Host Interface”
3. 在Host Interface 点击“添加”
4. 输入“VirtuakBox Host Interface #”（注：不输入引号，#号代表接口的数字，通常为1）
5. 点击OK
6. 关闭虚拟主机设置
II. Create a Network Bridge
Network Connections;à1. Open Control Panel
2. While holding down Ctrl select the Local Area connection and click on the VirtualBox Host Interface;
3. Right click on one of the selected connections; and
4. From the drop-down menu select Create Network Bridge
II.创建一个网桥
1． 打开控制面板-〉网络连接
2． 按下“Ctrl”键的同时选择“本地连接”和“VirtualBox Host Interface”
3． 在其中一个选择的连接上，点右键
4． 从下拉菜单里选择，创建网桥
Since I am using static IP’s on my network set up I had to configure the TCP/IP properties for the Network Bridge.
注：由于我的网络使用的是静态IP设置，因此必须配置网桥的TCP/IP属性
5. Right click on the Network Bridge that was just created;
6. Select TCP/IP;
7. Click on Properties;
8. Set the Static Connection Values; and
9. Close Network Connection.
5． 在刚刚创建的网桥上右击，选择属性
6． 选择TCP/IP
7． 点击属性
8． 设置静态IP地址的值
9． 关闭网络连接