From my experience, one of the best free (and also Open Source ) softwares for such purpouse is KeePass Password Safe.
Instalation and using on Windows platform is easy and user friendly.
Download and install Linux alternative from .deb file.
sudo dpkg -i KeePassX-0.2.1.deb
I encoutered problem with missing libQtXml.so.4 library (becouse KeePassx is build on KDE graphic engine)
sudo apt-get install libqt4-qt3support
This installs QT with all the library you need.
And that is all. Enjoy using.