Hosts adds a preference pane to your system preferences which lets you toggle your host file entries on and off, as well as add and remove them.
Get it on GitHub.
I wouldn’t have linked to this, but here’s an interesting bit from the developers’ blog about App Store rejections:
"Hmm, my evil plot failed. I managed to never become root and still edit /etc/hosts, but I got rejected, how is that fair? Ofcourse I sent in an appeal to the review board. As they stated, it does not matter that none of the code I wrote ever runs as root, thereby neutralizing any security risk. Rule 2.27 also means you can not authenticate as an admin either!"
Apple is trying to play super-safe. As the developer mentions in his blog post also, they are the ones who are responsible for the software they sell. If they sell a virus or malware, they are the ones who are blamed.