What packages are installed?

[Jose L Gomez Dans <j.l.gomez-dans@sheffield.ac.uk>]

Hi!
	I suppose this is a *very* basic question, but is there an easy way
to find out what packages are installed? I mean, I can go through
/var/lib/dpkg/available and figure it out. However, if it's a very "popular"
package, it'll take for ever. I tried using dpkg --print-avail, but this
does not seem to take wildcards.

	Any hints?
		Thanks,
		Jose
-- 
Jose L Gomez Dans			PhD student
					Radar & Communications Group
					Department of Electronic Engineering
					University of Sheffield UK