Task1.
Put a text file on the server (xml or similar) containig the version number and download link(s). Download that using a http get.
Code:
<?xml version="1.0"?>

<application>
	<version>1.2</version>
	<link>http://some.server.net/version12.zip</link>
</application>
Then download the file using Indy or similar.
http://www.indyproject.org/sockets/fpc/index.en.aspx

And finally unzip the zipped file
http://www.freepascal.org/packages/unzip.html

Note that the blizzard downloader uses torrent instead of http download wich is good if you are limited on band width. (They do have a fallback http link in case there is no seeders)