Originally Posted by Nate the great
Are you sure it has DRM? How did you get it, exactly?
Was it on a CD when it came with the paper book? Then it doesn't have DRM.
This. (I can't believe I'm saying "This" now. Next it'll be "+1.")
Also, if it was DRMed for a Kindle (which it isn't since you say you can read it in mobi[ocket reader), even buying or stealing a Kindle wouldn't help you. You don't need "a" serial number. You'd need "the" serial number that the file was encrypted for.
Just try converting it to an epub with Calibre and see what happens.
Otherwise, see Susan's comment above. If you can read it, you can convert it.