Velleman PC-Oscilloscope & Spectrum Analyser
The PCS100AU is a 32MS/sec, 12Mhz single channel digital storage oscilloscope, spectrum analyser and transient capture instrument, using a standard computer to monitor and display waveforms. All standard oscilloscope, transient analysis and spectrum analyser functions are available in the Windows program supplied. Comes with 110V power adapter. Connection is through a computer's parallel port. The scope is completely optically isolated from the computer port.
For more info see the PCS100AU Datasheet.