The charge alleges that DeLay and co-conspirators did their misdeeds on or about Sept. 13, 2002. The statute of limitations on the charge is three years, which meant the grand jury had to indict by Sept. 13, 2005.
The Smoking Gun has posted the indictment. Here's the pertinent graf:
The Grand Jury further presents that, with the advice and consent of counsel, the defendant, Thomas Dale DeLay, did heretofore knowingly, intelligently, and voluntarily waive the application of Articles 12.01 and 12.03 of the Texas Code of Criminal Procedure to the indictment presented herein. In particular, the Grand Jury present that with the advice and consent of counsel, the defendant, Thomas Dale DeLay, did knowingly, intelligently, and voluntarily waive the requirement that an indictment for the felony offense of criminal conspiracy, the object of which is a felony other than those listed in Subdivisions (1) through (5) of Article 12.01 of the Texas Code of Criminal Procedure, may be presented within three years from the date of the commission of the offense, and not afterward, insofar as such requirement pertains to the indictment presented herein.