Because they're worth it
The British Chiropractic Association v. Simon Singh (a relatively well reported news event) takes a new turn, the BCA have now released a list of citation showing evidence for chiropractic treatment.
This list is torn to shreds here, here, and particularly here.
To add my small contribution, as a librarian I looked to see what I could find of the journals cited - Journal of Manipulative Physiological therapy (the most frequently cited) is not held by any major research university in the UK (so far as I can see). Spine (another cited) appears to be published by chiropractors, and the reputable sources, as other bloggers have noted, appear to be irrelevant.
Chaff is the only way to describe that list. The BCA have exposed themselves, pass the word, let the world know, and if your friend is contemplating chiropractic treatment, just remember - the BCA had the chance to put up solid evidence, and demonstrably failed to do so.