We started to circle back this week to the geographical information systems stuff that we started a couple of weeks ago but got distracted by something that is really exciting.

Some time ago we noted that VMware had started a program to encourage people to create prebuilt virtual machines (or "virtual appliances" as VMware calls them) configured to do something useful.

While the first few appliances were interesting, the Virtual Appliance Directory and the Appliance.net repository show how useful and amazing virtual appliances can be.

In fact, VMware ran a competition called the VMware Ultimate Virtual Appliance Challenge. The competition was to create virtual appliances using any combination of open source or freely distributed software and/or the entrant's own code.

The contest attracted 169 entries. There were fist, second and third prizes along with prizes in the categories Collegiate, Consumer, Developer, Server and VMTN Community Choice. (VMTN is the VMware Technology Network; a VMware Web site hosting blogs, forums, the Virtual Appliance Directory and technical information on VMware products.)

The winners were way cool. First prize went to the HowNetWorks virtual appliance, a high-level network analyzer based on Ubuntu that comes with full documentation and training videos.

Second prize went to the Trellis NAS Bridge Appliance, an appliance that "makes it easier to access files from one location (i.e., a client) even though the files may be stored on different computers, different file servers and different operating systems [so that they can be] accessed by applications . . . as if they were local files."

The third prize winner was Sieve Firewall, a transparent bridging iptables firewall and netfilter traffic control configured through a Windows-based .NET GUI.

You have got to try these virtual machines, but you'll need one of VMware's players. While all of the appliances in the Appliance.net repository are available as regular Web file downloads, the majority of the appliances in the Virtual Appliance Directory are only available as BitTorrent downloads.

If you don't have the BitTorrent client and are wondering which one to use, you might like to check out the feature matrix in the Wikipedia entry for BitTorrent clients.