FactCheck.org is a great, unbiased site that's currently giving a lot of attention to claims about guns, "statistics" about gun deaths, etc. Their home page
has several relevant articles. In a box in the upper right corner, there's this, for example:
Q: Is it true that 85 percent of all the children killed by guns in the world are killed in the United States?
A: No. This statistic, misused by the husband of former Rep. Gabrielle Giffords, refers to a study of 23 high-income countries in 2003 that made up less than 14 percent of the world’s population.
Just an excerpt from a longer, and very thorough, article.
They also have have an entire section devoted to "Gun Rhetoric vs. Gun Facts."
They give both sides equal treatment, as far as I can tell.