You don't say which PIC device and there are lots. But the advice that follows is probably pertinant for most of the devices e.g. PIC16F84, PIC16F877 etc.
You will probably want to implement a serial interface on the PIC device using something like the MAX232 interface chip to generate RS232 level signals to and from the PIC device. (One can of course use 5 volts via the parallel port if you don't want RS232, but then it all becomes a bit P.C. specific).
Some code will need to be written to send and receive serial data on the PIC device and do some conversion somehow, depending on the A/D scheme.
A design that I saw for a PIC16F84 used a quad op amp for the RS232 interface, stole power for the PIC using the DTR and DSR lines. The A/D was implemented as an F/V convertor and comparator arrangement, all this was then multiplexed through a couple of DG208's (I think) for 8 input channels.
L.V. 6i will certainly do the P.C. side (based on significant personal experience in this area) so you should have no problems there.
You might try the following resources on the web, there are some good free utilities..... and using Google you can find inumerable free PIC programmer designs and tutorials.
http://www.mikroelektronika.co.yu
http://www.dontronics.com/index.html
http://www.dontronics.com/index_b.html
www.microchip.com
Hope this is the sort of help you needed.
