This is a plugin that I developed for use while researching HijackThis logs that are posted on the web. Just highlight a word and then use the right click context menu to search several malware databases and the results will open in a new tab.
Usage: Highlight some text (filename, dll, etc), right click and select "Malware Search" from the popup menu, find the database you wish to search, and then left click on that menu entry. A new tab will appear with the results. You can use the options menu to select which databases appear on the menu.