QtLogbook is a logbook spreadsheet application which acts like a spreadsheet, except that it mimics the look of your paper logbook. It also has a report window that helps you determine your pilot time in various aircraft types over different time periods - useful when filling in an FAA 2120 or an insurance pilot history form. It currently handles helicopter, ASEL, AMEL.
QtLogbook was written using the excellent cross platform Qt class library from Trolltech. I'd like to thank Trolltech for allowing their product to be used to produce high quality free software.