Parley.im is a desktop client for Facebook with lots of features including Invisible / Away mode, Instant notifications. Also has a birthday calendar and a photo browser / downloader. After all, this application was created to be as fun and as easy to use as possible.

Parley.im Features:
Facebook Chat
1. Invisible Mode - See who is Online while appearing Offline.
2. Away Mode - Sends an Auto Message everytime someone messages you while you are busy.
3. Supports Friendlists - Be Online to some while being Offline or Away to others at the same time. And group Friends.
4. IM Style Facebook Chat - Bigger Interface and windows to chat.
5. Flashing Windows - Whenver a friend sends you a message. Don't miss any chats anymore.
6. Friends Online Notification - A small popup alert everytime a friend comes online.
7. Fast and Stable - More responsive and stable than chating in any browser. Also list of Friends Online/Offline is more accurate.

Instant Notifications
Instant Alters - A small popup window alerts you when you receive a new mail, requests or comments.

Birthday Calendar
Calendar Module - Shows Birthdays of your friends. You can see all birthdays at once, or browse by month.

Album Downloader
Album Downloader - Download Entire Albums in a single click, it's easy and fast.

Photo Browse - Browse photos of all your friends from a single page.

Requirements:
* .Net Framework
* Facebook account

The license of this software is Freeware, you can free download and free use this blog software.