I was looking for a 64bit version PDF iFilter for a new MOSS implementation, and when I was doing my usual browsing through the blogging community the only references I found was to Foxit's iFilter. Not that the Foxit iFilter is bad, but why buy the milk when you can get the <insert noun> for free.
A client pointed this out to me - Adobe Labs has released software that will allow the 32 bit Adobe iFilter to work on MOSS 2007 x64. It's a bit "hacky", but pretty Easy to setup. My guess is that Adobe was getting a lot of guff for not having this out so they had to throw us a bone in the interim.
http://labs.adobe.com/wiki/index.php/PDF_iFilter_8_-_64-bit_Support