4×4 Inclinometer is an application for our Nokia N900 that is designed to measure the inclination from our N900 in our car. I like to use when i ride a bicycle to measure the slopes 
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Inclinometer is still in development, so you can download in the repository Extras-Devel, to know more about repositories, click here.
You can watch a video of the author with the inclinometer application running.
[youtube]http://www.youtube.com/watch?v=wrhcm3Yo-7k[/youtube]
More information in zimmerle.org.
where is link for download