While searching for a resolution regarding the Firefox Grease Monkey dilemma, I stumbled upon this Orkut Toolbar extension which I think every "Orkuteer" should have.
A little more about this useful tool from the site.
Orkut Toolbar helps you to format the text of your posts in the Orkut forums.
With Orkut Toolbar all you need is type your entire text without any formatting code and then select the desired parts of text and apply the format using the toolbar buttons. Much like you do in MS Word or any other text editor.
Created by Renato Rodrigues, this tool bar makes posting links and images (yes, I did say images!) within Orkut a snap.
I have already installed it, and it has made posting links and signatures much easier, instead of typing it all by hand or copying from a notepad on your computer.
For more information you can visit the Orkut Toolbar Forum or the Firefox forum.
Update: Listed feature underneath "Orkut User Tools" in the sidebar.