I previously wrote an article on how to get Casey's tactics manual onto your Blackberry.  Here's a list of field manuals used during the Civil War.  Let me know if there's anything you want me to add to the list.

• Hardee's Tactics Vol. I: Google books - epub - Mobipocket
• Hardee's Tactics Vol. II: Google books - Mobipocket
• Casey's Tactics Vol. I: Google books - Mobipocket
• Casey's Tactics Vol. II: Google books - Mobipocket
• Casey's Tactics Vol. III: Google books - Mobipocket
• The Volunteer's Handbook: Google books - epub - Mobipocket
• United States Infantry Tactics Manual (USIRT): pdf
• Bello's Manual of the Sword: pdf
• Howe's Fife & Drum Instructor: pdf

Google Books also lets you download pdf and epub files.  Mobipocket files are for the Mobipocket Reader for your Blackberry or other smart phone.

For more information, you can read an overview of the tactics manuals.