Unannotated editions of the Federal Rules of Criminal Procedure (FRCrP) are posted free by the U.S. Courts and the Legal Information Institue. The LII also posts the Rules in eBook format.
Annotated editions of the FRCrP are published at the end of Title 18 of the United States Code Annotated (USCA) and the United States Code Service (USCS). Lightly annotated editions are available in O'Connor's Federal Criminal Rules & Codes Plus, with commentary and Committee Notes (Jones McLure), in the "Criminal" rules pamphlet at the end of Moore's Federal Practice, with Committee Notes (Lexis/Matthew Bender) and in the softcover Volume 3D of Federal Practice and Procedure(West), with Commentary. An unannotated print edition is available in West's Federal Criminal Code and Rules.
Proposed and recently-approved changes to the Rules are posted on the Pending Rules Amendments page of the Federal Judiciary web site. Generally, new rules go into effect on December 1.