Questions About dpkg and friends

[Jeff Hornsberger <jhornsbe@csc.uvic.ca>]

Hi, I just moved over from redhat and am wondering about how to do a few
things in the debian package management system.
1) If you know the name of a file you need, but not what package it is
part of, what's the best way to find out what package you need?
2) Once you install a package, how can you get a listing of what files
in the system belong to that package?
3) How can you tell what installed package (if any) a particular file in
the system belongs to?
Thanks very much. -Jeff