The clash between state and national committees over the scheduling of state primaries has led the national committees of both parties to nullify the presidential delegates from certain states, though in differing proportions. There is speculation that the national committees will not adhere to this tough stance.

But in both parties, there’s a belief that whatever penalties are meted out will be voided when the conventions gather next summer. The hope is that party leaders will want unity, not division, going into the general election.
“The will of the convention in our system is paramount,” the RNC official conceded. “We are a creature of the convention of the grass roots of this nation.”

As things stand today, however, the Republican National Committee has deprived the following states of half their presidential delegates:
Florida
Michigan
New Hampshire
South Carolina
Wyoming
[Note: Iowa also moved its caucuses to January 3, ahead of the cut-off date, but was not penalized by the RNC because their caucuses are non-binding.]
And the Democrat National Committee has deprived the following states of all of their presidential delegates. In addition, all of the Democrat presidential candidates have pledged not to campaign in these two states, though this event has led to accusations that the Clinton campaign is following the letter, not the spirit, of the pledge.
Florida
Michigan
The New York Times has a handy chart with the dates of each party’s state primaries and the current status of the delegates from each state.
Republican Primaries & Delegates
Democrat Primaries & Delegates
[Thanks to commenter Anthony for reminding us of this interesting complication under Andrew’s post, “Open Thread: Republican Presidential Nomination”.]