mac os only: I worked to update SilverPing to v0.3. Now, it allows you to type special characters like "+" and "&" into your status updates, it has an installer program, icons, and a confirm dialog so you don't accidentally post stuff.
Silverping is a super easy way for you to post status updates to twitter, linkedin, facebook and more.
Ping.fm is a service that allows you to post your status update once and have it updated on myspace, facebook, twitter & more.
Quicksilver is an mac application for making everything (applications, web pages, repetitive tasks) very quick and accessible from your keyboard.