Several of us at SBIG have tried different methods for achieving quicker focus. Unfortunately, we have found that the best way still takes some time, especially the first time you try it. There are a number of different methods for getting approximate focus such as using a aperture mask or creating diffraction spikes. A mask consists of a piece or cardboard with two (or three) holes cut in it that fits over the aperture of your telescope. When a bright star is out of focus you will see two (or three) separated images, and as you get close to focus the images will appear to merge. Diffraction spikes are created by hanging two dowels or other thin strips of some material in front of the aperture of your telescope. When out of focus you will see two diffraction spikes and as you get close to focus the spikes will merge. We have tried both of these techniques and while they are good for getting close, they aren't very sensitive to fine focus. For this last bit of fine focusing we recommend using the peak value readout from CCDOPS described in the manual.
Once you have achieved good focus you will want to mark an eyepiece which is parfocal. Without changing the position of the focus knob, remove the camera and insert an eyepiece. If you are lucky, one of your existing eyepieces will be in focus as you slide it in and out of the draw tube. As you slide the eyepiece, note where it appears to be in focus and mark the barrel. Next time you set up you can use this eyepiece to return you to near correct focus for your camera. You will probably still have to use the peak value method to refine this focus every time you start an image session. Some users re-focus before every image, particularly with Schmidt-Cassegrain telescopes because the primary mirror can move slightly when you shift the position of the OTA. If you do not have an eyepiece that will come to focus at the same position as the camera and you will need to get an eyepiece barrel extension or a custom parfocal eyepiece for your camera.
Also, Ron Wodaski has written a great book on CCD Astronomy "The New CCD Astronomy" and has posted his chapter on focusing on the web for free download.