Keyring password clear/reset

Lucid 10.04

• Applications > Accessories > Password and Encryption Keys

• A window will open in the "Password" tab

• Select your keyring by clicking on it

• Right click on it and select "Change Password" to change or "Delete" to remove existing password

Here's a tutorial on doing this from the command line

Hardy 8.04

The Ubuntu Forms have a list of instructions here.