Yes, I use my 1Ds2 on a view camera. (A more complete thread on the gear I use can be found here: http://www.outbackphoto.com/tforum/viewtop...hp?TopicID=1481
Focusing can be a bit daunting at first. View lenses are slow, and the images they render are notoriously dark relative to the fast DSLR glass you are used to looking through. I shot with a view camera for several years, so I am used to focusing on a groundglass. Fortunately, the DSLR viewfinder is not much different than using a low power loupe on the view camera. My best advice is simply to practice, and with time you'll get the hang of it. Here are a few tips that should help...
1) It is CRITCIAL that your DSLR eyepiece diopter is set properly. To do this, use AF with a fast lens and focus on something in good light with detail about 20 feet away. Now adjust your diopter until the subject you focused on in the viewfinder appears crisp. Mark that setting and be sure it is set there whenever using the DSLR on the view camera.
2) As you focus your view camera, pick the most critical elements of your image to focus on, prefereably using an edge or high-contrast detail on same. As you rock the focus back and forth, you will see the image fall out of focus in both directions after a given amount of movement on your view camera focus knob. Note by feel about where these limits are, and position the knob on the mid-point between them -- you are now in focus even though you aren't sure you are. (Actually, as you develop a feel for this, you ideally want the knob 1/3 of the way from the near point to the far point, but when you are starting out half-way is good enough.) It's a Zen kind of thing and you will get the hang of it over time
3) You can also use a focusing aid like the Canon anglefinder C... HOWEVER! This device has to be properly set to your eyes too, and can be easily moved out of adjustment. Moreover, to properly adjust it, it must be set AFTER your diopter on your DSLR is properly adjusted. The big problem I find here is you end up dealing with two devices that can both be off a little and actually end up compounding your focusing error. For this reason I don't bother with it on the view camera and stick with method 2.
Hope this helps!