At 12:56 AM 7/31/2004, you wrote:

If I google for pdfTeX homepage, then I get the following link:

http://www.tug.org/applications/pdftex/

However, this must not be the official homepage as it seems to not have been updated in a long time and also does not mention anything about the available 1.20 version.

This is, as best I can tell, the official homepage. See below for why it's quite reasonable that it doesn't contain version 1.20.

Also I cannot find the file named pdftexlib.zip as mentioned in the user manual on the above site.

Where I can find the latest and greatest versions and documentatio on PDFTeX?

The official testing page, which contains version 1.20a-rc6 -- you'll note that version is still only a release candidate in testing, not an official release, which is undoubtably why it's not available on the official distribution site -- is at: http://pdftex.sarovar.org/ I find very few online references to pdftexlib.zip, and all of them are rather old, so I wonder if the files it contains are now included in with the rest of the standard distibution rather than being a separate file. I suspect that the documentation at http://www.tug.org/applications/pdftex/ is as up-to-date as exists. - Brooks