As table name you can also specify columns you want imported.

Will import all columns:
<?php
pg_copy_from($db, 'cpm.ics', $rows);
?>

Will import only specified columns:
<?php
pg_copy_from($db, 'cpm.ics (type, product, date, count, amount)', $rows);
?>

To solve the problem of how many backslashes to use for the parameters $separator and $null_as: The backslashes are interpreted twice, first by PHP and then by PostgreSQL. So write four backslashes to indicate one backslash in the input data. So both '\\\\N' and as "\\\\N" become NULL AS E'\\N' meaning the same as NULL AS '\N' in the internally used SQL statement.

The loaded input data must be backslash-escaped. According to the PostgreSQL documentation, you can use the following escape sequences:

\\ = Backslash (ASCII 92)
\b = Backspace (ASCII 8)
\t = Tab (ASCII 9)
\n = Newline (ASCII 10)
\v = Vertical tab (ASCII 11)
\f = Form feed (ASCII 12)
\r = Carriage return (ASCII 13)
\000 (Backslash followed by one to three octal digits) = the byte with that numeric code
\x00 (Backslash x followed by one or two hex digits) = the byte with that numeric code

With the default setting, a data field containing only \N (one non-escaped backslash and an N) indicates a NULL value. This default value \N has been chosen because it does not collide with properly encoded data.

When using this function, don't get bit by the double quote (") vs. single quote (') differences.  It is a small thing, but the error messaging is misleading.  If you use a single quote, you will see the \t separated values all try to be inserted into the first field.

Small consideration, but will save someone who is working late and can't get these functions to work.

see also: pg_put_line for a solution that does not require buffering of all the data to be copied,

Default is "\\\N" not "\\N" at least in php 5.4

pg_copy_from($db, $table_name, "\t", "\\\N")

By default NULL values are a backslash followed with capital N ("\\N"). 

Also, you can't insert entries with OIDs (I've added it to my TODO list though)

As of postgresql 9.1 "standard_conforming_strings" is set to on

This will not work anymore
<?php
$copy_message = "1\t\\N\t300";
pg_copy_from($db, "message", $copy_message);
?>
result will be a "N" in that field. if the field allow text that is else it will fail to insert the post.

simple fix
<?php
$copy_message = "1\t\\NULL\t300";
pg_copy_from($db, "message", $copy_message, "\t","\\NULL");
?>

pg syntax is :
COPY test (cola, colb, colc) FROM stdin;
...

this function doesn't let you in which order the columns are !

Something needs to be said about the format of the array.
Judging by what I've seen, it's pretty much what you get
from loading a tab-separated file with file(). That is, the
lines are linefeed-terminated and there's no need to have
an extra line with "\.". On the other hand, when I try using this
command the connection to the server ends up in some odd
state and is then lost:
PHP Warning:  U?S?o() query failed: server closed the connection unexpectedly

I think it might be safer to use the lower-level function
pg_put_line() for now.