Twitter will soon commence a cull of unused usernames on its service, and release them to the public - a policy that could spark a rush not unlike the Great Land Run of 1889.
Currrently, Twitter regards any account that hasn't been logged into or updated in over 6 months as 'inactive'. However inactive accounts aren't deleted - they just sit there gathering dust and spammy followers. A change in policy is on the way, however. A spokesperson told TheNextWeb that all inactive and deleted usernames will soon be released for others to use.
Previously, some special cases have been able to get squatted names allocated. Those cases contacted Twitter support and if they were judged as suitable then they were granted the name. Both @BBCNews and @CMU got their usernames altered in this manner.
No date has been set for the release, so if there's a particular name you're after then keep it bookmarked and check back regularly to see if it's been made available. It seems unlikely that Twitter would notify people of the date of release in advance, but if we hear anything, we'll be sure to let you know.