I think I know what you're on about. When learning the difference between the simple past and the present perfect, "already" is one of the words sometimes used to illustrate when (in BE) the simple past is not used, in cases like:
I have already done my homework.
But the example shows that there are other cases where already can be used that does not indicate the present perfect. The "real" reason for using the present perfect in "I have already seen that film" is because the time period being covered is "up to the present". When "already" refers to "up to a given point in time (not the present)" - e.g. the time point when you met the person you had already heard about, then a different tense is called for - here the past perfect, which indicates a period of time prior to a point in the past.
There's a lot of good stuff on this in grammar books for learners, which uses time lines to show how the tenses operate.
Here's an example: http://www.teachingenglish.org.uk/articles/ti...
(Incidentally, in AE, the use of the simple past here seems very frequent, though I don't know if it is considered colloquial: "I already saw that film".)