"Finally Adobe has come up with an interim solution to address the non-availability of a 64 bit ifilter. Now one can use the 32-bit Adobe IFilter on 64-bit platforms after installing a DCOM addin from Adobe. The installation instructions can be found on the Adobe Labs Wiki .
This is a great oppurtunity for folks who have a 64-bit installation of Microsoft Office Sharepoint Server 2007 and want to index pdf documents, but do not want to spend money on a 64-bit FOXIT IFilter."
Source: Filter Central