A recent posting to the TAS-Manchester Yahoo group mentioned Libhomeradar.
Perhaps a lot in this forum already know of it but I can't remember it being a topic here. Sorry for bringing it up if I'm the only one not to know of it but I think it could be of interest to Radarbox and SBS users, even if only to find the flight history of of any plane.
I was surprised at the comprehensive data which came up when typing a registration in the 'search database' section.
The home page is:-
http://www.libhomeradar.org/Regards,
Syd