Uninstall a plugin - by: antoine1003

Hey,
I am looking to uninstall a plugin properly (remove column added, reset uploaded file, etc..). This feature doesn't seem to be implemented, am I right? When we install a plugin it's for ever ?
Is there any way to do it? Maybe by adding a uninstall.php file in the root of the folder?

Thanks
(PS: I am sorry to post every day but it's kind of tricky...)
Antoine