Does it matters the column order in indexes and constraints creation?

Hi all,

I've got a doubt about how to create an index and a primary key. Lets
say I have the following table:

CREATE TABLE blacklist
(
telephone VARCHAR(15),
customer_id INT4
CONSTRAINT fk_blacklist_customerid REFERENCES
customers( customer_id ),
country_id INT2
CONSTRAINT fk_blacklist_countryid REFERENCES
countries( country_id ),
CONSTRAINT pk_blacklist_cidcustidtel
PRIMARY KEY(country_id, customer_id, telephone)
);

The country_id column can have maybe 100 - 250 different values.
The customer_id column can have as much several hundred values (less
than 1000).
The telephone is where all will be different.

So my doubt is, in terms of performance makes any difference the
order of the primary key fields? The same in the index definition? I
have checked the postgresql documentation I haven't been able to find
anything about.

Thanks
--
Arnau