Real simple. Seat the delegations as if the primaries had counted but with the following two conditions:
1. the popular vote in those two state primaries are irrelevant and have no impact on the party's nomination process.
2. all delegates not selected for Senator Clinton will be allocated to the only other remaining active candidate, Senator Obama.

Why?
Get it out of the papers and off TV and move beyond it. Then why take the next two steps.
1. The popular vote is disregarded because the primaries took place outside party rules and therefore the primary never took place as far as the nominating process is concerned. No candidate should be advantaged or disadvantaged by the outcome of the vote.
2. The party wishes to ensure the people of these two states are represented at the convention and some method for selection of delegates is necessary to ensure that representation is present. Senator Clinton, despite the agreement of all candidates, kept her name on the ballot in Michigan and thus should be presumed to have received all the votes she would have received under any other scenario. Senator Clinton made appearances in Florida in the week leading up to the voting there and thus can fairly be assumed to have garnered as many votes in that state as she would have had all candidates been present in the state in the week leading up to the primary. If a revote were to occur in either state, only two names would be on the ballot, Senators Clinton and Obama. We therefore safely can assume that the balance of delegates would have been Obama delegates and will therefore seat the remainder of the states' delegations on that basis.

Senator Clinton will be accorded her 80 delegates in Michigan and her 113 delegates in Florida. Senator Obama will be accorded the balance: 77 delegates in Michigan and 98 delegates in Florida.

reference:
http://www.thegreenpapers.com/P08/MI-D.phtml [1]
http://www.thegreenpapers.com/P08/FL-D.phtml [2]