This adds a new feature -- the ability to repost journal entries from one account to another, whether you are on Livejournal or elsewhere. You can select as many entries as you like to transfer -- from one to all. Select only entries with certain keywords using find; select only certain security levels; etc.
The transfer has some limitations. The biggest one is that comments will not transfer. That significantly limits the usefulness of this feature, but it seems that some would still find a post-only transfer to be useful. There's a good chance custom security groups won't transfer either (though you can try). If transferring cross-server, features not supported on the receiving server obviously won't transfer, either. The rest should transfer pretty nicely.
As usual, LJ-Sec requires the .NET framework 1.1 and IE 5.0; all posts also must be in Unicode in order for LJ-Sec to sync right (you can convert older posts here). The Mono compatible fork, for experimenting on other platforms, has also been updated.
Find the download for LJ-Sec at http://www.mp3vcr.com/ljsec/.