I cannot open attached emails (such as those in .eml format) in iOS mail, but I seem to recall this working in iOS 4. (Can't remember for sure.) Is anyone else having the same problem? For me they just show up as garbled pieces of headers, not even as attachments.
For more information see Can iOS open .eml files?
View the Correct Answer Cannot open .eml attachments (attached RFC/822 email messages) in iPhone Mail-iOS 5.1 in iPhone errors Answer , Ask iPhone Mail, Contact , Calendar Question