How can I install themes for Terminal?

I am rather new to Mac, but I am trying to get familiar with Terminal and I want to change its theme. I am a bit confused on how to go about installing Solarized themes I am seeing so much of around the net. I am able to get the theme installed for vim, but I want it for just my general terminal usage.

I see some suggesting to install SIMBL but then I read if you have Lion, SIMBL is not needed with the color support that it has.

And then I've seen a suggestion to just "double click" to install, I am not entirely sure what is meant to be double clicked, the Solarized Dark ansi.terminal file?

My concern is running something that I am not sure what it is going to do. So anyone who could shed some light on this process, that would be extremely helpful!

Just open up terminal, go to the preferences and select the theme (the .terminal file)

Double-Clicking a .terminal file will not "run" anything, it will just install the configuration in Terminal. At the end you will get to the same result by double-clicking and by importing the settings from Terminal directly.

Using the 'save link as' option on the Github site for these themes didn't work, as noted in another answer. I dug in and noticed that the XML file formats were different when comparing the export of built-in themes and the ones I was trying to import.

When I did the Download .zip (the link is on the RHS of the main github window) and expanded the .zip file, it resulted in getting Solarized Dark.terminal and Solarized Light.terminal files which were import-able.