I disagree that the best way would be a pdf. It will end up much bigger than it needs to be. Instead use dump or dput to create an ASCII text representation and save that to a .txt file that you attach. The mime_part
{sendmailR} is used to construct attachments. You could also use mime_part.data.frame and bypass constructing the dump()-ed or dput()-ted steps.
You can find a worked example here: http://www.inside-r.org/node/95009
## Not run:from <- sprintf("<sendmailR@%s>", Sys.info()[4])
to <- "<olafm@datensplitter.net>"
subject <- "Hello from R"
body <- list("It works!", mime_part(iris))
sendmail(from, to, subject, body,
control=list(smtpServer="ASPMX.L.GOOGLE.COM"))
## End(Not run)
If you want to examine code that attaches a pdf file then look at mime_part.trellis
{sendmailR} which send a pdf print
-ed() from a trellis/lattice object.