After getting a few requests from users to make Clippings work with the recent Firefox 2.0 beta 1 release, I have uploaded an experimental build of Clippings 2.0 with the maxVersion value in the install manifest incremented.
The XPI is available from here: http://downloads.mozdev.org/clippings/experimental/fx2-b1/
A few issues have been identified with Firefox 2.0b1 compatibility; please see the readme file. I have also opened bug 24715.
A minor release of Clippings to coincide with Firefox 2 is in the works. In the meantime, it is recommended that only testers, early adopters and advanced users (the same type of users who would be using a Firefox beta release) should download and install this experimental build of Clippings into Firefox 2.0b1.