Remote Assistant is available from the Pentax website.
http://www.pentax.co.jp/english/supp...d_digital.html
Note that there are only 2 downloads, for the K10D and *ist D.
I did download the *ist D version for my *ist DS and it worked fine until Pentax revised the *ist DS Firmware (from Version 2.0 to 2.2 IIRC) and then it ceased to work on the *ist DS, so they must have “crippled” the firmware as the software was only intended for the *ist D.
Fortunately, I had a back up copy of Version 2.0 Firmware which I re-installed in the camera
Cheers
Dennis