Hello 
You can find some Soundcard oscilloscopes software that require no hardware to be attached to the pc. You need only one sound card and some connectors to drive the signal at the input of the sound card of your pc.
Check here: http://www.electronics-lab.com/downloads/pc/index.html
Additional pc oscilloscopes:
Non Commercial
http://www.ee.washington.edu/conselec/CE/sp95reports/guterman/final/scope1.htm
http://www.geocities.com/huz_52/
http://home.planet.nl/~m.f.hajer/
http://www.discovercircuits.com/O/oscilloscopes.htm
http://www.geocities.com/tangmonster911/oscilloscope.htm (ISA bus)
http://www.dansworkshop.com/Homebuilt%20oscilloscope.shtml (TV based)
http://www.geocities.com/SiliconValley/Lakes/7156/articl3.htm (with LEDs)
http://www.electronic-projects.net/Electronic-Projects/projects/telescope/index.shtml (TV based)
http://www.intio.or.jp/jf10zl/tvosc.htm (TV based)
Commercial:
http://www.qkits.com/serv/qkits/velleman/pages/pcs500.asp
http://www.scope4pc.com/
http://www.acqiris.com/Products/Cougar_main.html
http://www.picotech.com/oscilloscope.html
http://www.designnotes.com/Specials0702.htm
http://www.usb-instruments.com/ (USB)
http://www.arborsci.com/Products_Pages/Software/PCOscilloscope.asp
http://www.linkinstruments.com/oscilloscope21.htm
http://www.bitscope.com/
You can find some Soundcard oscilloscopes software that require no hardware to be attached to the pc. You need only one sound card and some connectors to drive the signal at the input of the sound card of your pc.
Check here: http://www.electronics-lab.com/downloads/pc/index.html
Additional pc oscilloscopes:
Non Commercial
http://www.ee.washington.edu/conselec/CE/sp95reports/guterman/final/scope1.htm
http://www.geocities.com/huz_52/
http://home.planet.nl/~m.f.hajer/
http://www.discovercircuits.com/O/oscilloscopes.htm
http://www.geocities.com/tangmonster911/oscilloscope.htm (ISA bus)
http://www.dansworkshop.com/Homebuilt%20oscilloscope.shtml (TV based)
http://www.geocities.com/SiliconValley/Lakes/7156/articl3.htm (with LEDs)
http://www.electronic-projects.net/Electronic-Projects/projects/telescope/index.shtml (TV based)
http://www.intio.or.jp/jf10zl/tvosc.htm (TV based)
Commercial:
http://www.qkits.com/serv/qkits/velleman/pages/pcs500.asp
http://www.scope4pc.com/
http://www.acqiris.com/Products/Cougar_main.html
http://www.picotech.com/oscilloscope.html
http://www.designnotes.com/Specials0702.htm
http://www.usb-instruments.com/ (USB)
http://www.arborsci.com/Products_Pages/Software/PCOscilloscope.asp
http://www.linkinstruments.com/oscilloscope21.htm
http://www.bitscope.com/