With iCombiner you can merge documents directly in Finder using the contextual menu.
To use this feature, first install the Finder plugin:
1. Install the Finder plugin by choosing iCombiner > Preferences and clicking Install
2. When asked if you want to restart Finder, click "Yes, restart now"
You can now merge files in Finder by selecting them, Ctrl-Clicking and selecting the "Merge to PDF..." item.