Here is the summary information for how to access the secret servicing firmware menu of the K10D and how the AF focusing offset can be changed via the menu:-
http://www.pentaxforums.com/forums/pentax-dslr-discussion/3158-k10d-service-menu-af-adjust.html
For more about what is this about and why it is there, see my last blog article:-
Focus Calibrations for (Pentax) (D)SLR Bodies and Lenses
Well, by entering the camera into the servicing mode, no special software utility is required nor the camera is needed to be opened (although it is very easy for this, only the bottom plate is required to be opened), and, of course no (special?) connection cable is needed.
I haven't tried this with the K10D nor I have tried this with my K100D. So, I can't verify if the above procedures exactly work or not but it seems that it should work anyway. Also, although the posts mention about K10D firmware V1.10, I wildly guess that the steps should be applicable for current Pentax K series DSLRs or even for the older *ist Dx ones, because those secret key stroke sequences are usually the same for entering the secret mode for the same line of products for a manufacturer, for many electronics products.
Nonetheless, for anyone who would like to try, he/she is reminded that he/she should drop down all the parameter values before making any changes and anyone should be fully aware of the risk for accessing the servicing menu, which might ultimately screw up things and the process may not be reversible. So, again, the typical old warning words follow: DO IT AT YOUR OWN RISK!
Bottom line is IF you DON'T face *any* problem, do NOT try it. That's my humble advice. But I think I would still like to share this piece of valuable information here, for those who might need it or find this interesting for some reasons.
Update (Feb. 12): Here comes the latest post by M.S. Shin for how to enter the secret menu of *ist DS/DS2, DL/DL2, and K100D, for a *different* set of procedures required. (So, the K10D is actually in a category of its own.) Enjoy! (for just reading or hacking :-))