Try EBay.
I have a Radioshack meter with an RS-232 interface, and love it !
It shouldn't be a problem. You just send simple text commands to the meter
and read back the ASCII result.
So any language will do. For example I once used tow of these meters to
generate a battery discharge graph.
I just set one to voltage and the other to current and sampled both every
couple of minutes.
I'll get you the model number of my meter and post it here.
It really is a piece of cake to use.
I don't think they are made anymore so you may have to resort to EBay.
The infrared for Rx/tx is for electrical isolation of the computer connected serially from the circuit under test. Without it there is the possibility of blowing up your host computer...
Kevin P. Hannan
AmeriCare Homecare
678-823-8155
www.americareinfo.com/ga4
Smyrna, GA
My Meter is a Radio Shack (Micronta) 22-168A Multimeter
Other Meters:
http://www.tubedepot.com/tl-72-7735.html
http://cs-sales.net/vedibemuwirs.html
http://www.testequipmentdepot.com/extech/multimeters/mp530a.htm
http://www.elexp.com/tst_s345.htm
Software Links:
http://www.linuxastronomy.org/lias/prg/dmm_me11/hp/dmm_02.html
http://www.linuxtoys.org/dvm/dvm.html