How to find out the version package available on website

[Stephen Liu <satimis@icare.com.hk>]

Hi folks,

Kindly advise how to find out the version of a package available to upgrade/
install.  I am not quite clear on man apt-cache.  I tried follows without 
result;

# apt-cache -v firebird
E: Invalid operation firebird
# apt-cache-v firebird
-su: apt-cache-v: command not found

# apt-cache pkgnames-v firebird
E: Invalid operation pkgnames-v

apt-cache pkgnames -v firebird
firebird-s32-server
firebird-c64-server
firebird-examples
firebird-s64-server
firebird-c32-server

apt-cache search -v firebird
firebird-c32-server - FireBird Classic w/ 32bit I/O - RDBMS based on InterBase 
6.0 code
firebird-c64-server - FireBird Classic w/ 64bit I/O - RDBMS based on InterBase 
6.0 code
....
....
zope-kinterbasdbda - Zope Database Adapter for Interbase/Firebird
...
etc.

TIA

B.R.
Stephen Liu