Crawling PDF content within your MOSS 2007 environment requires a bit of configuration. I came across two posts from Microsoft that describe what needs to be done using Adobe Reader v.8.

• Indexing pdf documents with Adobe Reader v.8 and MOSS 2007 [Filter Central]
• Icons are not displayed for Adobe PDF documents.... [Microsoft Help and Support]

Of course, Adobe has since released Adobe Reader v.9. While the steps are essentially the same, I wanted to post my steps for reference (or until Adobe Reader version 10 or MOSS 200x is released).

1. Download and install Adobe Reader v.9.
2. Navigate to 'Configure Search Settings' found in your Shared Services Administration application.
3. Click on 'Manage Files Types' to show the file types included in the content index, then add pdf as a new file type
4. The PDF Filter registry key value is still {E8978DA6-047F-4E3D-9C78-CDBE46041603} under Adobe Reader v.9
5. Replace HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office server\12.0\Search\Setup\ContentIndexCommon\Filters\Extension\.pdf with value in Step 4
6. Replace HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\12.0\Search\Setup\ContentIndexCommon\Filters\Extension\.pdf with value in Step 4
7. Update your PATH environment variable to include 'C:\Program Files\Adobe\Reader 9.0\Reader;' or the installation directory used in Step 1
8. Recycle the search service from the command prompt - 'net stop osearch' then 'net start osearch'
9. Recycle IIS from the command prompt (not sure if this is required, but I found it handy) - 'iisreset /noforce'
10. Download pdf icon file from http://www.adobe.com/misc/linking.html
11. Save the icon to 'C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\12\Template\Images' folder
12. Edit DOCICON.XML found in C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\XML
13. Add <Mapping Key="pdf" Value="NameofIconFile.gif"/> inside the <ByExtension> node and save the document
14. Perform a full crawl on your content sources