Sitecore 8 is great product compared to previous versions of Sitecore. But, it comes with some glitches, this is one of them.
There might be several reasons for Sitecore to hang on publish. Below are the most common ones:
- Make sure permissions for your packages folder in Data folder are right.
- Make sure your MongoDB server is up and running and can connect from the web server.
For previous versions of Sitecore, this blog post might help - publishing stucks
Please let us know if it did not fix the issue.