Ellen, check the top post out here for some other related advice:
I haven't tried any Lightroom plugins myself, though I have been curious. Can anybody recommend any plugins they've used with Lightroom (I do not have Photoshop) that they've found particularly helpful and a good value?
While placing them into the Modules folder works, it means the Plugin is always there.
C:\Program Files\Adobe\Adobe Photoshop Lightroom 2.3\Modules
If you create a folder called Lightroom Plugins (anywhere e.g. in My Pictures or Pictures), you can then use the Plugin Manager (File Menu>Plugin Manager) to install and remove any plugin.
1. Lightroom 2 can work with export plug-ins regardless of where they’re located, but it’s easiest if you put them in one of the following folders:
• Mac OS: /Library/Application Support/Adobe/Lightroom/Modules
• Windows XP: C:\Documents and Settings\username\Application Data\Adobe\Lightroom\Modules
• Windows Vista: C:\Users\username\AppData\Roaming\Adobe\Lightroom\Modules
To install a plug-in, simply drag it into one of those folders, and then launch Lightroom. Lightroom will automatically find the plug-in and make it available.
2. Use the Plug-In Manager to enable/disable plug-ins. Choose File > Plug-In Manager or click the Plug-in Manager button in the Export dialog box.
3. To use an export plug-in, click the double-pointing arrow ( ) at the far right of the Files On Disk button that straddles the top of the Export dialog box. Then, choose the plug-in from the list.
4. Some plug-ins have additional functionality that is available by choosing Plug-In Extras from the File, Library, or Help menu.