There was a download of OpenAnno 2008.01 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The most frequent installer filename for the software is: OpenAnno.exe. This free program is a product of OpenAnno Team. The program lies within Games, more precisely Simulation. The following version: 2008.0 is the most frequently downloaded one by the program users. We recommend checking the downloaded files with any free antivirus.
From the developer:
The OpenAnno project aims at creating a free and open source realtime economy simulation with strategy elements in an isometric 2D engine loosely oriented towards Sunflower’s Anno series. The Unknown Horizon project aims at creating an open source realtime economy simulation game with strategy elements in an isometric 2D engine loosely oriented towards Sunflower's Anno series.
You may want to check out more software, such as VoxATC, FS2Crew: Wilco-Feelthere Airbus Special Edition or FS2Crew: FSX PMDG 747 Edition, which might be similar to OpenAnno.