The circuit is straight forward. The 10k LIN variable resistor is at the ends connected to the + and - so that the PIC input can cover the full range. This because the AD routine can only convert a voltage. So whatever you want to measure the resistance of it has to be connected in such a way that it acts as a voltage divider.
http://members.home.nl/b.vandam/lonely/pagina7.html
Here's a clever design idea lifted from the pages of Electronic Design. Stephen Woodward has designed a circuit that allows one pot to adjust two channels.
http://www.web-ee.com/Schematics/DualChannelPot/DualChannelPot.htm
How to use the PC to connect to a Nutchip in order to read a remote control, to sense a smart-card, to enable outputs or to read inputs? Here are serial communication secrets, from the protocol to a working example. Source code is provided.
http://www.nutchip.com/progetti/vb_sample/vb_sample_en.htm
http://www.qsl.net/n9zia/wireless/appendixF.html#11
A circuit that limits the rate of change of a signal; a feature of this design is that the positive and negative rates can be different.
http://freespace.virgin.net/ljmayes.mal/pubs/slew.htm
http://home.cogeco.ca/~rpaisley4/LM3909.html
http://jnaudin.free.fr/html/gseadiag.htm
The easiest way is to use resistors. A two way matching network uses a 43.3 ohm and 86.6ohm resistors
http://www.old555.com/LPE/unit/77866AD477405881.shtml