Visual Analyser: Virtual Oscilloscope :)

Visual Analyser is a complete professional real time software, transform your PC in a complete set of measurement instruments; no new hardware necessary (you can use the Sound Card of your PC) or you can use a specific external hardware.

Virtual CD/DVD Drive: Virtualize Optical Media

    Virtual CD/DVD drives creates images of your optical media, so you can use 

them at any time without having the physical medium on hand.

In many important works we need these virtual drives.

There are many Virtual CD/DVD Drive softwares available on internet.

Bellow are some good Virtual CD/DVD Drive Softwares:-

Virtual Printer

A virtual printer is a piece of computer software whose user interface
and API resemble that of a printer driver, but which is not connected
with a physical computer printer.
When a user requests that a document be "printed" by a virtual
printer, then, instead of having the document printed on paper or other
material, the underlying software would process its contents in some other
way, often resulting in a file being produced or the information being transmitted.

It Save a document to another format such as a PDF file.

Bellow are some good virtual printer Softwares:-

Virtual Router -Wifi Hot Spot For Windows7

Project Description
Virtual Router turns any Windows 7 or Windows 2008 R2 Computer into a Wifi Hot Spot using Windows 7's Wireless Hosted Network (Virtual Wifi) technology.
What is Virtual Router?
Virtual Router is a free, open source software based router for PCs running Windows 7 or Windows Server 2008 R2. Using Virtual Router, users can wirelessly share any internet connection (Wifi, LAN, Cable Modem, Dial-up, Cellular, etc.) with any Wifi device (Laptop, Smart Phone, iPod Touch, iPhone, Android Phone, Zune, Netbook, wireless printer, etc.) These devices connect to Virtual Router just like any other access point, and the connection is completely secured using WPA2 (the most secure wireless encryption.)

Where can Virtual Router be used?
Anywhere you are!
Home
Office
School
Airport
Bus Station
The Park
Grandmas House
The In-Laws
Absolutely Anywhere!
No Advertising, No Hassle
Unlike similar applications, Virtual Router is not only completely Free, but will not annoy you with any advertisements. Also, since Virtual Router is not ad-supported, it does not track your web traffic the way other ad-supported applications do/can.

The Wireless Network create/shared with Virtual Router uses WPA2 Encryption, and there is not way to turn off that encryption. This is actually a feature of the Wireless Hosted Network API's built into Windows 7 and 2008 R2 to ensure the best security possible.

You can give your "virtual" wireless network any name you want, and also set the password to anything. Just make sure the password is at least 8 characters.

BTW, this project is written entirely in C#.
( http://virtualrouter.codeplex.com/ )

PC-based oscilloscope (PCO)

   Oscilloscope software running in Windows that uses the computer's sound card as a cheap ADC
Although most people think of an oscilloscope as a self-contained instrument in a box, a new type of "oscilloscope" is emerging that consists of a specialized signal acquisition board (which can be an external USB or Parallel port device, or an internal add-on PCI or ISA card). The hardware itself usually consists of an electrical interface providing insulation and automatic gain controls, several hi-speed analogue-to-digital converters and some buffer memory, or even on-board DSPs. Depending on the exact hardware configuration, the hardware could be best described as a digitizer, a data logger or as a part of a specialized automatic control system.