Here's an R tutorial where I explain how to read Stata data files into R (even if you don't own the program Stata). I also offer some other basic tips.
Of note, you can also write Stata .dta files from R (if your coauthors or journals insist on having ".dta" data).
Suppose your R data frame has the name fuzzybunny and you want to save the file to the C: drive as myfuzzydata.dta. After loading the foreign library,
Here's the syntax:
Try it out and impress your friends (you know, the friends who only know how to use Stata).