Using xchat:
1) Downloading
You can go to the following link:
http://www.xchat.org/and then click on the "Download XChat" link
OR
you can download xchat directly from here:
http://www.xchat.org/files/binary/win32/xchat-2.8.3e.exe2) Installing
After you finished downloading you just start the program (installer) you download.
Click "next", leave the components as default - "Next", "Next" again and then click on "Install".
After that click Next one more time, leave the "Run XChat" checkbox marked and click "finish"
3) Configuring
You'll get a dialog like this one:

Insert your nick, the second nick (usually the first nick + _ (underslash)), the username and the real name (or just write something)
From the network List, select
freenode and then click
Connect4) Joining the channel
After connecting you'll get a dialog like this one:

Select the second option (
Join this channel) and write
#astralpulse, then click OK

That's it

Those who prefere the web interface and don't have problem with it can still go to:
http://java.freenode.net//index.php?channel=astralpulse