via srz_bznz on Insane Journal:
You can have the little LJ-code icon on any Journaling site and have it link to the correct journal, be it on LiveJournal, InsaneJournal, GreatestJournal, DeadJournal, JournalFen, or Blurty, courtesy of the Fake LJ-User Tag page.
Here's some examples:
This is InsaneJournal liz_marcs
This is GreatestJournal liz_marcs
This is JournalFen liz_marcs