Hi Duncan .... stacking your images is essential with a DSLR. I didn't believe it when I started imaging but it is true.
Here is a link to DSS
http://deepskystacker.free.fr/english/download.htm
Your camera should have in camera noise reduction for long exposures ... if you turn that on then you will not need to take separate dark images ... it just means you will be waiting longer in between shots while the dark frame is subtracted from your pic by the camera.
Flats are evenly illuminated images that negate any dust spots on your chip and any vignetting in your images ... there are articles about taking flats on IIS and other sources.
A cable release is also essential to avoid camera shake and lock your mirror up as well during your exposures.
I think that's about all for taking the images ... you are embarking on a long journey and have just taken the first tentative step.
Another journey is processing ... but that's another story for another day
Good luck and clear skies !
