After long time waiting finally some good news for N900 owners. MeeGo for N900 will soon be released and available for dual boot with Maemo but without support for the MeeGo-enabled N900. The update will be available on the MeeGo site, which should enable dual-booting of Maemo and MeeGo on the Nokia N900 so you can get a taste of the upcoming MeeGo mobile OS.
On the Maemo side, there have been interesting, supporting developments going on, as well. The PR 1.3 update is quite close now, and with that you can easily dual boot between Maemo and Meego on your N900. There is also a possibility of developing applications supporting both operating systems, based on Qt and Qt Mobility APIs on the Maemo side.