Cell phone privacy guide for Android
The Pirate Party of Canada has a nice list of applications and add-ons for Android phones which enhance security and privacy. It boils down to
- Use Cyanogenmod.
 - Install applications from the alternative FOSS market F-Droid. All of the applications below are available directly from F-Droid.
 - Set up a network firewall with Droidwall.
 - Use Firefox, with NoScript and AdBlockPlus add-ons.
 - Set application permissions with Permissions (aka. Permission Denied).
 - Send encrypted SMS with TextSecure.
 - Encrypt your files with Android Privacy Guard (AGP).
 - Send e-mails with K-9, which also supports PGP.
 - Encrypt folders with LUKSManager (not on F-Droid?).