there is no program that is good just for that camera...it depends on what you wanna do with the picture. i will always say photoshop for intensive editing, photomatix for HDR's, and lightroom for workflow/light editing. adobe lightroom and apple's aperture is essentially the same program and i highly recommend them. its easy to organize your files, it doesnt edit your original picture(huge plus), has all the adjustments you need for basic touch up's.
as for rolling shots, you want to shoot in shutter priority mode(gotta check the manual on what it is for canon). the basic rule of thumb is to set your shutter speed at the mph your car is traveling at(ie. 1/50 shutter speed at 50mph). for extra blur, use a shutter speed thats half the mph youre traveling. i tend to shoot around that, but its hard to get many good photos..i usually only get 1 good one out of 10ish. if its really sunny out then you may need to adjust your exposure value to get a proper exposure. it might be too sunny outside to use a shutter speed low enough to get a decent background blur while not over exposing he image. thats just something to keep in the back of your mind if you come across that situation.