How do you form commands in Polish?

How do you change the verb into a command?

I know some like słuchaj and chodż(sp?) from listening to some people say it to me or others.

But what is the general rule for all commands?

In polish is known as "tryb rozkazujący".
For example:
chodzić(walk)-chodź
słuchać(listen)-słuchaj
mówić(speak)-mów
robić(do)-rób
jeść(eat)-jedz
General rule? I don't know the rule. It's rather irregular.

In English this is called the imperative. I think there is a general rule - you take the 3rd person plural form of the verb and then drop the "ą" ending. For example:

chodzić is chodzą in the 3rd person plural, so you need chodz as your base for the imperative.

Likewise słuchać goes to słuchają, thus słuchaj. Also jeść goes to jedzą thus jedz.

I read a good lesson on this but can't remember where - I am sure it's covered in the Uni of Pittsburgh lessons somewhere though.

Me neither :(
but quickly anylising some examples given (and other verbs) I tend to assume it's the 3rd person plural (= they) form minus the ending, of course some minor changes between related vowels/consonants appear now and then (like it happens quite often in Polish, in such cases other forms help too), sometimes 3rd person singular is very helpful, especially with those more irregular verbs.

Let's take tczesio's examples:
infinitive - 3rd plural (present tense) - imperative mode:
chodzić - chodzą - chodź (not chodz, but the soft "dź/dzi" appears in other forms as well)
słuchać - słuchają - słuchaj
mówić - mówią - mów
robić - robią - rób (why "ó" not "o", it would require some knowledge of old, medieval Polish, to explain this process, I guess it's nothing a beginner would care about)

jeść - jedzą - jedz

other verbs:
iść - idą - idź ("dź" instead of "d", but it's for example "on idzie" with soft "dzi", so no wonder this "dź" found its way :)

wiedzieć - wiedzą - wiedz
jechać - jadą - jedź (here the 3rd person singular "on jedzie" looks like the direct source of the imperative form, but I guess it's down to some old Polish again, to explain why such a form is used)

If you want to use the imperative form to more then one person, then you add the ending -cie to the basic imperative form. In first person plural you add -my. In the polite form (with Pan/Pani [or plural Państwo]) you use "niech" + pan/pani [or państwo] + 3rd person singular [plural] indicative mode.

John, give me some time. - John, daj mi trochę czasu.
Guys, give me some time. - Dajcie mi trochę czasu.
Let's give him a lesson - Dajmy mu nauczkę.
(Sir,) don't talk to me like this, please. - Niech Pan tak do mnie nie mówi.
Gentlemen, trust me, please. - Niech mi Państwo zaufają. Technically zaufają is future tense, but it's because it's a perfective verb, so it has no present tense, but with a imperfective verb you use the present tense:

Gentlemen, don't lie to me, please. - Niech mnie Państwo nie okłamują.