I installed Dowser on my iBook a few weeks ago (binaries are available for OS X and Windows, or build from source – requires Python, SQLite, and PySQLite).

Dowser runs as a mini local web server (uses a browser for UI) that organizes searches using Google, A9, etc. and clusters results. A handy right side menu shows topics discussed in the search results. These topics are links to locally cached previous search results – this mechanism allows cross referencing your search results by automatically assigned topics. Anyway, Dowser is worth a look.