Mozilla Labs have just released their preview version one of Snowl 0.3, a prototype universal messaging and content aggregation plugin for Firefox. Mozilla have tweaks the program more, and it promises more stability than previous version.
This version integrates Snowl better with Firefox's feed aggregator. It looks a promising product. It would be nice to have only one client for all messaging/content aggregation services on the web. Check out Mozilla Labs's blog post about Snowl 3.0pre1 and download the plugin here. Please note that you need Mozilla Firefox 3.5b to test out this plugin.