Its the only way
This saves me a ton of time when trying to find one teeny-tiny piece of code in a mountain of files. There are several similar plugins but this one struck me as the simplest and best. It searches all the files under a certain directory for a string you enter. You can get it here:
To install, download and extract the compressed folder, then put the files file-search.gedit-plugin, file-search.glade, and file-search.py in your plugins directory. For local use, this will be in ~/.gnome2/gedit/plugins/, or if you want to install system-wide put them in /usr/lib/gedit-2/plugins/ (you have to be su to do this). Activate the plugin in Gedit by going to Edit > Preferences > Plugins and putting a check next to File Search. You will now have a new menu item under Search called Find in files… Have fun with that!