To preview PDF-files in Outlook you can install the latest version of Adobe Reader. This includes a preview handler that is compatible with Outlook 2007 and Outlook 2010.
Download: Adobe Reader
Search inside PDF-files
To be able to search inside PDF-attachments in Outlook, you must install an iFilter for pdf-files. When you are using a 32-bit version of Windows, this is automatically installed when you install the latest version of Adobe Reader. For a 64-bit version of Windows you’ll need an additional installer.
Download: Adobe PDF iFilter 9 for 64-bit platforms
The 64-bit PDF iFilter will also enable searching inside pdf-files in server products such as Microsoft Office SharePoint Server, Microsoft Exchange Server, and Microsoft SQL Server.