Being a Linux user, I was very happy to see the release of Google Desktop for Linux. So I ditched Beagle and switched to Google Desktop.
As you probably know, Flock comes with full text indexing of your web history. It works very well, and is integrated with the search bar which is very cool. But if you want to have your web history indexed, you can do it thanks to Flock's compatibility with Firefox. Just follow the instructions on Google's help pages.
Windows: replace "Mozilla Firefox" by "Flock", "Mozilla" by "Flock" and "Firefox" by "Browser"
Linux: just go to the directory where you untarred Flock and follow the instructions. You can also put the file email@example.com in your home directory, personally I prefer that
Most of the time, unless it's related to bookmarks, what works for Firefox also works for Flock.