1. You need firefox browser with Greasemonkey extention.
2. You can perform these tricks ONLY ON Mozilla Firefox v 1.x or later.

Install All in One script from here ..

It has the following features :

1)encrypt or decrypt ur message from bottom of any text box.(community, scrapbook etc)..

2) 3 cool fonts, can be selected from bottom of text box.

3) scraps can automatically be made colourful..(from bottom of textbox)

4) IT also changes image links to images in scrapbooks and community posts.

5)It gives a link 'refresh scraps' on the top menu of orkut.
when this link is clicked, the page doesn't refresh but just the link refreshes.
it will show you the number of scraps in your scrapbook.
if you find that the count increased, click on the same link to directly go to your scrabook (no matter where ever you are on orkut).

6) It also shows a small link called 'signature' below every text box.
when you press it, your signature will be added at the end of the scrap or community post.
IT also works in 'reply' text box in you scrapbook....
to modify the script, install it and edit with notepad.
modify "your name" in 106th line to your name.

7) this script also installs few cool links on top menu !

This script was taken from Crazy Souls