Thanks to the Legal Information Institute at Cornell University Law School and the Center for Computer Assisted Legal Instruction’s eLangdell Press, you can download the current versions of the Federal Rules of Evidence, Federal Rules of Criminal Procedure, and Federal Rules of Civil Procedure for free.  The books are available in .epub format, which is compatible with most e-readers including iPads, Nooks, and Android devices.

Here are direct links to each book:

2015 Federal Rules of Evidence
2015 Federal Rules of Criminal Procedure
2015 Federal Rules of Civil Procedure