Snow Leopard came with fetchmail, but in Mountain Lion seems to be missing. Homebrew doesn't have a formula for it either.
What's the best way to get back fetchmail?
Homebrew does have it, but it's in the separate homebrew-dupes repository. So to install:
brew tap homebrew/dupes
brew install fetchmail
the following gist is a formula which will address this issue. if you go to the aforementioned link (to download the fetchmail source code) and place it into /Library/Caches/Homebrew and then run the gist. you'll get the homebrew version of fetchmail.