There are a ton of freebies out there. A couple of the ones I have installed on my Android phone are:
1. US Army Survival Manual (23 chapters plus appendices)
2. Survival Guide (US Military Survival Manual FM 21-76)
3. Daily Survival Tips (submitted by survival enthusiasts)

1 and 2 may be redundant...

The last one I present with caveats. While a number of the tips are useful, some are also dangerous and send out mixed or incorrect information. Use with care. The real usefullness of these tips is that it keeps you thinking everyday about survival issues and thus keeps you on your toes.