2-10

That's the count of states that will seemingly have to change their gun laws:

Two states (Illinois and Wisconsin) flat out prohibit carrying concealed weapons. It seems impossible to square this with what other states are doing, so "equal protection" looks like it will force a change.

Ten states (Hawaii, California, Mississippi Alabama, Maryland, Delaware, New Jersey, New York, Connecticut, Massachusetts, Rhode Island) are "May Issue" states - a CCW license might or might not be granted to the applicant, based on local law enforcement whim. The majority SCOTUS finding that it is the equal protection clause that applies to incorporation seems significant here.

I expect it will take some time for the details to get digested. There are a bunch of opinions, and a lot of pages in them.

UPDATE 27 June 2010 17:41: Alabama, not Mississippi is a "may issue" state. Fixed in the post. Thanks to Lweson in the comments for pointing out the error.