There are two parts here:
It appears that GPass is dropped in oneiric so can anyone recommend a new password manager?
Is there a way to open the file created with GPass, or do I need to recover the passwords in another install of GPass and manually move the passwords into the recommended replacement?
I have been trying out a few password managers.
Revelation can import gpass databases and even looks and works the same as gpass.
It is in the repositories in oneiric.
It imports gpass (otherwise known as Gnome Password Manager), passwords just fine (the user below's problems notwithstanding). I just did it.
To import from gpass click File->Import. Browse to your .gpass directory, pick your passwords.gps file, and pick 'Gpass 0.5x or newer' as the filetype. (It does not seem to automatically detect the filetype). Enjoy.
You can use this PPA for gpass:
https://launchpad.net/~stanray/+archive/gpass052
I didn't have any luck getting Revelation to import my gpass password file, so i just installed the natty version of gpass from here.
http://linuxappfinder.com/package/gpass
Download the .deb file, double click on it. After install all runs as before.
Hope it helps,