from version 1 to 1.1.638 you can find it on official website
http://simcity.ea.com/update/index_u...=EP1&x=57&y=18
choose the sku1 update for this exe version (North America)
however, to get the 1.1.638 to 640 you need to register (with serial) to get the file. it's a small patch that actually patches 3 files, one of them is the executable. I have uploaded the small patch on rapidshare.
http://rapidshare.com/files/22186427...e4BAT.zip.html