Start by reading this guide on how to perform a File and MySQL backup for your Pligg website.

Lets take a quick moment to discuss domain name servers. When you manage a domain you have tell the domain where it should look for hosting to connect to. Name servers are used to point the domain toward the proper host to show the official content for that domain. When you move hosts you will need to edit your name server settings for the domain so that they point to the new host. Making these changes can take “up to 72 hours” for everyone on the internet to be properly pointed to the new web host. However I have never had to wait more than an hour for me to see the changes take effect, but the propagation time will be different depending on your internet service provider (ISP). As an example Comcast cable subscribers might see your old web host while Road Runner cable customers might see the new host. Hopefully your webhost will allow you to upload the files and set up MySQL databases without having the domain name servers transferred. This will allow you to upload all of the files and make sure that everything works before doing the name server switch to point everyone to the new host.

Some web hosts allow you to set up a free subdomain (Dreamhost uses a subdomain.dreamhosters.com format) other hosts have an IP address that you can navigate to so that you can see the new server before changing name servers. You should set up your site and confirm that everything is working before changing the name servers for your domain.

After you have the Pligg files uploaded to your host you will need to edit a few files so that Pligg will be able to connect with your new MySQL database. Open up /libs/dbconnect.php and edit the values for lines 2-5 to match your new MySQL database.
PHP Code:
<?php
define("EZSQL_DB_USER", 'username_here');
define("EZSQL_DB_PASSWORD", 'database_password_here');
define("EZSQL_DB_NAME", 'database_name_here');
define("EZSQL_DB_HOST", 'localhost');
if (!function_exists('gettext')) {
function _($s) {return $s;}
}
?>
If you have changed the domain or what folder Pligg is installed in you will also need to edit the /settings.php file to reflect the changes. Make sure though that after you get the site running that you also change the “Location Installed” settings from the Admin > Configure page of Pligg because this file will frequently update itself using the database settings.
PHP Code:
<?php
$my_base_url = 'http://YOUR-DOMAIN.com';
$my_pligg_base = '/subdirectory'; // remove /subdirectory if installed on the site root
$dblang = 'en';
define('table_prefix', 'pligg_');
include_once mnminclude.'settings_from_db.php';
?>
Besides uploading all of the files you will need to import the MySQL into the database. You will need to log in to the new host’s phpMyAdmin page and navigate to the Import tab (next to the export tab used earlier). Select the zip file you saved earlier from either using phpMyAdmin or from using SSH and upload it to phpMyAdmin. Unless the size is too large it should only take a few minutes to upload and add all of the tables to your database. Navigate to your Pligg site’s admin panel and everything should be working.

As mentioned a few paragraphs ago you may need to edit a few options from the Admin > Configure page at this point. After you confirm that everything is working go ahead and change those name servers from your domain management page so that your domain will begin to point to the new host.