It will not be public nor will it be under oath.
There will be a transcript however. Jonathan Turley is waxing poetic on this new development on Countdown. Video when available. From the link:
The agreement calls for Rove and Miers, Bush's top political adviser and White House counsel, to testify before the House Judiciary Committee in closed depositions "under the penalty for perjury," said House Judiciary Committee Chairman John Conyers, D-Mich. The committee says it also might call the two for public testimony.
I want to see Karl in prison orange...in the worst possible way.