You will need
  • Computer, microphones, audio cables, adapters.
The best solution is to buy professional entry-level audio interface. Such devices are inexpensive and available in different versions. There are options to connect to USB, Firewire, PCI, and PCI-E ports. The choice depends on your goals and on the configuration of your computer.
The best option is to buy an external interface with built-in MIC preamps. Typically, these devices come with a set of drivers, allowing you to simultaneously record and reproduce a signal from multiple inputs and to process various audio effects. If bought this audio interface, you will only need microphones and cords to them with the XLR (three-pin).
You can use external MIC preamps that connect to a common audio Board of the computer via line-in stereo input. The signal of one of the microphones when it comes on the left channel and the other on the right. For this you will need an adapter with a mini Jack (TRS 3.5 mm) - two RCA jacks (known as "Tulip").
All other options have been calculated on a fairly low budget, the quality will also be low, but emergency suit and they are.
Often two microphone connectors had a Chinese DVD player with karaoke function. If one of them you have, you can connect its line out with a stereo cable to the line input of your computer by connecting via the adapter as in the previous embodiment, and the microphones attach to the respective connectors on the player using cords XLR-TRS (Jack 6.35 mm). The quality of amplification from budget Chinese art is not very high, and the microphones from this country are highly susceptible to interference and feedback (high-frequency whistle from falling signal to the speakers into the microphone), but when working with headphones and a suitable option.
One could solder a small circuit with common shielding (negative) wire and separate the wires plus. All you need is a stereo cable, stereo jacks-Jack, two monarshey and, of course, a soldering iron and duct tape. But be aware that the signal level will be with this method of connection is extremely low and the noise level is high.