virtualbox.org

I want to create some virtual servers that I start as needed on my development box.
The servers should look like real iron on the network. For me that means I need static
IP addresses that I can add to my hosts file.

And now I wonder which is the best way to do that? On the Ubuntu wiki I found:
"With the most recent version of Virtualbox, 2.1.0, this entire thread is out dated.
...
No need to manually bridge your network card, no need for a tap,..."

And on the VirtualBox website I found an article that uses the tap interface.
(http://www.virtualbox.org/wiki/Advanced ... king_Linux)

Since I'm not a network expert I want to know if the Advanced_Networking_Linux
is still the way to go for a setup described above.

As the publication date of the wiki is from 2007, when version 1.4.x was about there (not sure, as I joined here since 1.5.x), it's needless to say that it's outdated big time. For the best info, read the manual, chapter 6. The Ubuntu Forums is more accurate, as you no longer need a bridge and virtual adapters for Host Interface, or Bridged as it's now.

Using the host interface works like a charm except that I don't know the IP my
network interface gets from the DHCP server. I tried a network alias but it didn't
work.

I thought about a adding an additional Ethernet card to get an interface which
could get a static IP but I would prefer a software solution.

Am I the only one who uses a DSL connection to the internet and wants
to use some local servers to test something?

If you read up on tcp/ip, routers, routing and local IP ranges you will find its extreemly easy what you want, IF, you have a router in use with your DSL. If you are directly connected with 1 machine to 1 internet connection then go and buy a router.