It's not quite what you were after, but there seem to be (at least) three K-x IR intervalometer solutions that have been discussed on the forum that might be useful to you. However none (alas) allow direct PC > K-x control:
(1) the Palm shareware linked above;
(2) the
Pcclix intervalomater
(3) the Gentled IR intervalometer discussed
in this thread, which works a treat, but is stand-alone.
In the end I guess you may not need to use the laptop if all you want to do is just for example set off the shutter automatically every 30 seconds over a certain period of time. Any of the devices above will do that task just fine.