LinkedIn has partnered with IBM to create a new plugin that integrates its professional social network into Lotus Notes, a popular business desktop client that includes Email, calendar, and IM functionality. The plugin is making its debut to the public at Lotusphere, with plans for its release in the first half of 2009.

For users who spend much of their day ‘living’ in their Email client, the new plugin could be a welcome addition. Its primary purpose is to display information relevant to the people in your Emails, as well as providing a handy way to browse through some of LinkedIn’s most oft-used features (like your news feed and search). However, the plugin does not yet automatically look up the contacts mentioned in your Emails – you’ll still have to click on their names or use the pre-populated search to look them up (automatic lookup is planned for a future release).

The two companies are also announcing LinkedIn integration into Lotus Connections (an internal social networking product for businesses), as well as an option to launch a Bluehouse web conference directly from someone’s LinkedIn profile. Both of these features are slated for some time in 2009, but the companies couldn’t give anything more specific.

For those of you who aren’t Lotus users, check out Xobni, which added LinkedIn support to its Outlook plugin last year. LinkedIn has also built an Outlook toolbar which you can find here.