I have read a few things about using campden tablets (potassium or sodium metabisulphite) in tap water to remove chloramines but I cannot find any articles with hard data on if and how it works.
Does anyone have some solid information they could share? Has anyone had their water tested by Ward Labs after using campden? Can Ward even test for chloramines? Does the potassium or sodium metabisulphite have any effects on the quality or taste of the beer?
No effect on flavor at all used in the proper amounts.
John Palmer briefly discusses this topic in his book. I’m not a brewing chemist (nor do I play one on TV :D), so I don’t know how it works, but it works! I do know that you don’t want too much sulfite in your finished beer because it can stunt or kill the beasties. 
How to Brew by John Palmer
http://www.howtobrew.com/section1/chapter4-1.html
If you’re curious about the chemistry, search HBD for posts by A.J. DeLange. He explains it better than anyone.
This may be slightly off from chloramine but here’s a small discussion on it:
http://www.homebrewersassociation.org/forum/index.php?topic=565.msg6662#msg6662
You might want to consider skipping the tablets and using the powdered Sodium Metabisulfite. It’s a little cheaper, and easier to use for amounts of water that aren’t in 5-gallon increments. I’m not near my bottle but, if recollection serves, I use 1/4 teaspoon per 5 gallons. I know that’s not as accurate as weighing it out on a gram scale, but it’s the closest approximation I can achieve without one.
I sure hope that the powdered stuff is way way less dense than the tablets. A 1/4 teaspoon would hold several tablets and the normal dose is only a quarter of a tablet per five gallons.
It is considerably cheaper, but it looks like I’d better re-check my math on the quantity… :-[