Spaz is an open-source desktop Twitter client for Mac, Windows and Linux.

Features:

• Cross-platform: available on all AIR-compatible platforms: Windows, OS X, and Linux
• Open source software using a New BSD-style license (source available at Spaz Google Code project site)
• Written in pure Javascript, XHTML and CSS. Utilizes the powerful jQuery Javascript framework
• Built-in global search powered by Summize
• Short URL creation tool with support for multiple services (is.gd, bit.ly, snurl.com, and more)
• In-line short URL decoding
• No ads
• Markdown syntax support
• Multiple themes and support for user-created themes
• User-defined CSS overrides
• Event sounds using the Tokyo Train Station soundset by Dominik Dimaano
• Directory listings of users you’re following, and your followers.
• Debugging and development tools and debug logging

The Good:

Spaz sports an easy-to-use UI and a bunch of great features. Being open-source allows for developmental tweaks.

The Not-so-Good:

We like Spaz a lot, but it does make use of our friend Air, and if Air goes wonky for a while, things get sticky.

Tweetwave.com rates it: ♦♦♦♦