Free circuit schematics - wiparat.com

This simple circuit allows you to record any IR remote control signal on your PC, and then play it back. This is particularly useful if you want to control appliances such as TVs, VCRs, CDs etc. from your computer. The device simply connects to the parallel port of your PC. You can also use this [...]

Simple, low component count tone generator. It can be adapted to create a morse code circuit, by adding a switch to the output.
This circuit is based around the 555 timer circuit, used as an astable (free running) oscillator. The frequency (pitch) of the tone is set by the resistors and capacitors in the left side [...]