Finally we have a 64 bit PDF IFilter - surprisingly the solution is not from Adobe or Microsoft, but from a company called Foxit Software.The IFilter is compatiable with the following Microsoft products: Windows Indexing Service, MSN Desktop Search, Internet Information Server, SharePoint Portal Server, Windows SharePoint Services (WSS), Site Server, Exchange Server, SQL Server and all other products based on Microsoft Search technology.

 There's one simple workaround to get the filter running on 64 bit MOSS 2007. The steps are given below.

1.       Install Foxit 64bit PDF Ifilter. http://www.foxitsoftware.com/pdf/ifilter/

2.       Add a pdf extension in MOSS search settings

3.       Open regedit, locate [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\12.0\Search\Setup\ContentIndexCommon\Filters\Extension\.pdf]

4.       Change the default value to {987f8d1a-26e6-4554-b007-6b20e2680632} .

5.       Recycle the search service: net stop osearch
                                              net start osearch

6.       Start a full crawl to index your pdf documents :)