The lowest frequency is 78 Hz, the highest one is 4652 Hz. For the mathematically inclined this means that Analog to Digital conversion takes 180 uS for zero volts and 7720 uS for 5 volts.
http://members.home.nl/b.vandam/lonely/pagina43.html
This device is a microprocessor controlled waveform generator that can be used for driving a voltage controlled stereo panner for music applications. Panning is simply the movement of a mono audio signal between the left and right channels of a stereo sound system.
http://www.solorb.com/elect/musiccirc/wavgen/index.html
A little software application for you to generate a signal of different frequency and amplitude.
http://www.e-dsp.com/software-functionsignal-generator/
A simple and inexpensive circuit and a simple C program are all you need to turn your PC printer port into a programmable frequency generator. Using a few low-cost and readily available components, the circuit occupies little space and is easily attachabl
http://www.edn.com/article/CA170222.html
http://www.musicfromouterspace.com/analogsynth/coolnewlfo.html
ramp generator, phase oscillator, quadrature sine/cosine oscillator
http://www.4qdtec.com/wfg.html
http://www.intio.or.jp/jf10zl/wien.htm
http://octopus.freeyellow.com/sine.html