This is nowhere near similar to what happened with Bush/Kerry. Actually, I don't think this sort of situation has ever occurred in our lifetime.
The deal is that the DNC determined that only certain states could hold their primaries before February 2nd (I think that was the final date -- they went back and forth on it a few times, so I don't remember). Howard Dean, the chair of the DNC, advised the states who were pressing the issue that if they insisted on holding their primaries prior to the agreed-upon date, they would not be allowed to seat their delegates.
Florida and Michigan decided to move forward with their newly scheduled dates (which were before the date specified), and as a FAIR consequence, they will not be allowed to seat their delegates. At least, that's where it stands as of today.
Some angry delegates, along with Florida Governor Crist, and Hillary Clinton, are calling for the DNC to rescind the punishment and allow these delegates to be seated at the DNC Convention. The opponents assert that Florida and Michigan's DP knew the consequences and now they have to pay the price.
A proposed resolution is to allow both states to hold a second, binding primary election, which would allow those delegates to be seated. Another proposal (informal, thusfar) is to split the delegates evenly between the two candidates.
To answer your question, I don't think they should hold another primary, and I don't think the delegates from those states should be seated.
