Hello,
I just have installed SL-6.0 from DVD images taken from there:
http://ftp.scientificlinux.org/linux/scientific/6.0/x86_64/iso/
http://ftp.scientificlinux.org/linux/scientific/6.0/i386/iso/
SHA1/SHA256 checksums match, and installation process doesn't bring any issues.
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wbr, Denis.