Hello,
currently I'm in testing stage of new webpage.
There is some CMS that could only run on one domain but I had already bought package of domains like: xxxxxx.pl, xxxxxx.eu, xxxxxx.net and xxxxxx.info.

What is the easiest and the best way to set up these domains?
The main service is running under .pl
Should I use 301 redirection on rest domains or maybe something else?

Regards
Jacek

Yes, your best option is to 301 redirect the other domains to the primary domain.

ok, I had seen different "implementation" of 301 - .htaccess, php file, html file.
which one is the best and why?

thanks and regards
Jacek

Yes 301 is the best to redirect you than any other domains....

yacenty, none are better than any others.

I would venture to say if you're looking for the "best" one it would be .htaccess. The reason is, Apache will process this file before loading up any PHP processes and executing them, so it could be argued that it is less resource intensive. However, if your server is unable to handle a PHP script that simply does a header redirect, you'd have many more issues in that case anyways.