I would like to ocr and index tiff files on my windows 2008 server. Is there any way to install tiff iText filter available for Win 2008 R2?
No, you can't use the R2 TIFF iFilter on "vanilla" Windows Server 2008. You could look around for thrid party solutions. OpenText has one, but I don't know the system requirements.
I would consider upgrading to R2.