The Electronic Freedom Foundation released a statement recently telling users of OpenPGP based products that they should disable or uninstall the plugin in their email client. One of the affected products was Engimail plugin for Thunderbird, which is what I use. Now mind you, I do not use encrypted email at all, I do maintain a key, but I have never used it for anything other than a few test emails with friends. I do however think it is important have a plan in place, you just never know when such a thing might become useful.
While this is kind of a big deal, it is also very easy to protect yourself against. I do not think it is particularly necessary to disable the plug in or uninstall it, unless you are either very paranoid, or know for a fact someone is attacking you. The moral of this story is, please be careful out there, but don't panic, it is probably not as bad as you think.
The Mozilla Foundations update on this issue: