This is mainly for my own reference in case I manage to botch up the installation process like what I did yesterday (thanks [Edrei] for the tech support!)

Step 1:
Download the Pidgin Twitter Status, Pidgin Facebookchat and the Microblog-Purple plugins (if I’m not wrong, you may be able to just go into Terminal and do a sudo apt-get install pidgin-microblog without needing to add any extra repositories).

Step 2:
For the Facebookchat plugin, simply install the .deb package you downloaded. Microblog, if you installed it via terminal, should already be enabled. Create your new Facebookchat and Twitter accounts via Accounts > Manage Accounts. Check that the plugins are activated by selecting Tools > Plugins > Twitgin. Configure your plugin to your liking and then let loose. Leave the Twitter Status one alone for now. You’ll be needing it later.

Step 3: (This is where it gets a bit complicated. Also requires Internet Connection)
Double check that Perl is enabled for Pidgin. This is done by clicking Help > About and scrolling down to Library Support. Perl should be enabled.

Step 3a:
Open Terminal (if you closed it earlier) and type: sudo perl -MCPAN -e shell (The sudo is required so the system recognises you as admin and allows you to change your usr/lib and other folders).

Type yes when prompted for auto configuration. Now, when that’s done, type Install XML::XPath

Step 3b:
Done? Now type exit and leave your perl shell and terminal.

Step 3c: (This is a bit tricky)
Depending on how your Ubuntu is setup, your plugins folder can be in either one of two places:

/home/usernamehere/purple/plugins (which is where it was for [Edrei])
usr/lib/purple-2 (which is where it was for mine)

You might want to chmod 777 your folder if it is locked (this requires terminal again, so please google Chmod 777 as I am too lazy to write it out here). Open said folder. It will be the one containing all your Pidgin plugins, so the folder will be plugin something or will have the names of your plugins within.

Step 4:
Remember that twitter.insertnumberhere.pl file aka that Twitter Status plugin? Now, drop it into the folder with your Pidgin plugins. Restart Pidgin. Head to Tools > Plugins and activate it.

Step 5:
Create a status (if it’s not already created) called Twitter in your Saved Status and begin updating.

Congratulations, everything should be working now. If it’s not, well, that’s what the Ubuntu Forums are for. I will have to say though, that the plugin MAY be unstable, but I will confirm that later, because my Pidgin crashed I think when I was asleep.