Depends on how your state does primaries. TN distributes delegates by U.S. Congressional district and you vote for the delegates.
The new electronic ballots may allow them to eliminate FRED from the ballot before 05FEB08. I hope not.
On to the brokered convention.
If you check the Tennessee Secretary of State office you will find that Fred Thompson (as well as Duncan Hunter and Tom Tancredo) are still on the Republican primary ballot. This is due to the fact that the absentee ballots are typically mailed out 20 or more days before the election. Of course that does not include time to actually certify and produce the absentee ballots after the slate of candidates has been determined. The actual cut-off date for including a candidate on a ballot was December 11, 2007 in Tennessee. In other words, if a candidate withdrew before Dec. 11, he or she would not be on the ballot.
All but 7 States allow for write ins, even on e-ballots. Those that do not allow for write ins, should be voted either in person at your local Registrar’s office, or by absentee ballot.