I can't seem to find the otr plugin in for pidgin 2.2.1. Does anyone know where I can get it?

Install the package pidgin-otr .

I tried that, but it seems that my computer can't find this plug in. I assume that I don't have the right addresses in my sources list. Does anyone know what source I am missing?

In your Terminal write:

sudo apt-get update; sudo apt-cache search pidgin-otr

If it shows the package everything is fine just do "sudo apt-get install pidgin", if not please check your Software Sources or your /etc/apt/sources.list

Nothing showed up. So I ask now, what source do I need to add that has the pidgin updates, or is there a main server location that I need to add that has a lot of other things

Ops, sorry pidgin-otr is in Universe. Go to System > Admin > Software Sources and activate the Universe Repository.

Would you happen to know exactly how to do it once you get to the Software Sources page?

In Software Sources in the tab that says Ubuntu Software mark the Community Maintaned Open Source software (universe)

All of the options are already selected.

I get the following error when I run the sudo apt-get update:

Failed to fetch http://repository.debuntu.org/dists/feisty/Release Unable to find expected entry multiversemultiverse/source/Sources in Meta-index file (malformed Release file?)
Reading package lists... Done
E: Some index files failed to download, they have been ignored, or old ones used instead.

Pidgin-otr isn't on feisty, please consider checking this http://screencasts.ubuntu.com/MoS2007/11_Updating_and_Upgrading