I have one similar to this one
IR Wireless Remote for Nikon D60 Canon 400D Pentax K10D - eBay (item 250375167129 end time Feb-23-09 15:45:38 PST). I am sure it functions with the K20 as well but do some research.
It is small but I don't think it is as small as the remote that Pentax sells. It will not hide in the compartment of my Travor battery grip.
It basically will operate the shutter only, which was all I wanted it for. If you have the camera programmed correctly, you can push the button, the camera focuses and then the shutter is activated. This remote has no shutter lock for long exposures and I have not found that any other buttons have a function for the K10. It is somewhat of a multiple brand remote design so perhaps it has other functions for other cameras.
I have yet to see if it will work my dvd player or tv but my neighbor's garage doors were going up and down just now as I push buttons with it aimed at his house. Interesting.
(justkiddingaboutthegaragedoorthing)
edit: It just occurred to me that on the example of the remote above, there are tiny letters such as P, C and N which must mean these buttons and their functions relate to Pentax, Canon and Nikon in their respective areas on the remote. See what you get when you stop and think for a minute?
Last edited by Nowhere Matt; 02-18-2009 at 02:04 PM.