How do I uninstall OmniWeb?
Just delete the OmniWeb application from wherever you installed it. OmniWeb also writes it’s supporting files like bookmarks, history, workspaces, and cookies in the following location within your home folder: <~/Library/Application Support/OmniWeb 5/>. The preferences file is also located in your home folder at <~/Library/Preferences/com.omnigroup.OmniWeb5.plist>. And finally, the cache files are located in this folder inside of your home folder: <~/Library/Caches/com.omnigroup.OmniWeb5/>.