President Obama is working to address gun violence on the federal level, but The Guardian has made a comprehensive graphic detailing gun laws on the state level across the country. Click over to their site to scroll across the laboratories of democracy — represented in the images here equally on a wheel, though you can scale by population — and see what sort of gun laws each state has right now, upcoming legislation after Newtown notwithstanding. While the outermost circle will contain the kinds of regulation the states have on the books, the innermost shows the states' attitudes toward carrying guns in public. Most regulation is concentrated in the Northeast.
Nearly all states allow people to carry guns both in both an open and concealed fashion (scrolling over the state will show the nuances of those laws).
Those nuances are also detailed in a chart below the main graphic: