The House Judiciary Committee filed a lawsuit in federal court: House Judiciary Committee v. Harriet Miers et al, a while back.
No, it's not a joke..its a court order. From TPM Muckraker:
Harriet Miers is not immune from compelled congressional process; she is legally required to testify pursuant to a duly issued congressional subpoena from plaintiff; and Ms. Miers may invoke executive privilege in response to specific questions as appropriate.
and that. . .
Joshua Bolten and Ms. Miers shall produce all non-privileged documents requested by the applicable subpoenas and shall provide to plaintiff a specific description of any documents withheld from production on the basis of executive privilege consistent with the terms of the Memorandum Opinion issued on this dateDon't you just love the smell of pissed off Republicans early in the morning? Remember, its better to be pissed off than pissed on...