KeePass Password Safe is a free software password management utility for Microsoft Windows, with unofficial ports for Linux, Mac OS X, and a variety of other systems. (Wikipedia)
They way I like to use this password manager, to ensure I don’t get caught out when on the move or using public computers is as follows:
Store KeepPassX (cross-platform port) executables for as many flavours of OS as is possible on Google Drive
Store database file in Google Drive
Run KeePassX from a .dmg image kept in Drive, pointing to the database in the OS X filesystem (thanks to Google Drive client). I have a short AppleScript that mounts the .dmg, opens KeePassX and unmounts on close.
On Android: Pin database file for offline use in Google Drive client, use KeePassDroid to read (read-only!) this file for password access on the move. Offline files (pinned) are typically located in: