NetZump Messenger Plugin
For Firefox 2 or above. IE in Windows XP above.
For other browsers, use bookmarklet
Drag this link: Netzump up to your Bookmarks Toolbar.
How to Use:
Menu
Your Friend's List
You can select friends to send your current page URL
Chat
You can chat with your friends by clicking 
URL of the Current Web Page
You can bookmark the URL (the link) by clicking 
Message
Type a message to send to your friends.