Whoa, I hadn't seen that, that is not correct as far as I know..  Any Intel processor that adheres to the EM64T standard (basically all of their modern ones) is 64-bit.  "Core" and "Core 2" don't enter into that. 
http://www.intel.com/performance/desktop/extreme/em64t.htm
http://en.wikipedia.org/wiki/EM64T

from the Wikipedia article:

The following processors implement the Intel 64 architecture:

• Intel NetBurst- Intel Xeon (some models since "Nocona")
• Intel Celeron D (some models since "Prescott")
• Intel Pentium 4 (some models since "Prescott")
• Intel Pentium D
• Intel Pentium Extreme Edition
• Intel Core microarchitecture- Intel Xeon ("Woodcrest")
• Intel Core 2

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