Eclypse recognizes the embedded plurals tag in a strings.xml file which is typically used when localizing an Android applications. Simply include your plural keys in the same strings.xml file as you normally store non-plural keys.

Example:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello!</string>
    <!-- example plural key -->
    <plurals name="numberOfItems">
        <item quantity="one">%d item found.</item>
        <item quantity="other">%d items found.</item>
    </plurals>
</resources>

See also:

Android string resources