What software does the tutor use in the Javascript videos?

He's using Google Chrome and a text editor. In Chrome, you can go to the hamburger menu on the top right of the menu bar, hover over more tools and click JavaScript console to get your web browser to look like his. I would suggest doing the Website Optimization course to learn more about it. That can be found here: http://teamtreehouse.com/library/website-optimization

If you're talking about the text editor, i think it's sublime text 2.

Sublime Text 2 is the text editor.

I think it looks more like TextMate rather than sublime - available here: http://macromates.com/

It's not TextMate, it definitely is Sublime Text 2 (or 3).

You can get the last version here: http://www.sublimetext.com/3. The trial version does not have any limitations but shows a "Please purchase this!" message after every 4 or 5 times you save a file.

It's a great multi-language code editor that can be extended with a lot of different packages/plugins that make it possible to do all sort of cool things. Two good examples of extremely useful packages:

1) LiveReload (https://github.com/dz0ny/LiveReload-sublimetext2): Having a browser page be refreshed as soon as you save changes to a JavaScript, HTML, CSS or other project related file, making it easy to run your code without having to switch between your code editor and browser. Just put Sublime and your browser side by side and start coding!

2) SublimeFTP" (http://wbond.net/sublime_packages/sftp): makes it possible to upload/download files to a server through FTP using a simple key combination.

3) Emmet LiveStyle (http://livestyle.emmet.io/): links CSS files you are editing to CSS files that are currently being used on a web-page, making Sublime Text edit the CSS directly in the browser (i.e. refreshing the CSS as you type!). This one tends to be a bit buggy but has been a life saver more than once while debugging CSS.

I use it for JS, CSS, HTML, Python, PHP and Node.js development.

I should mention that installing packages is not as straight forward as one would like, but as soon as you understand how the "Package Control" module of the application works, it's relatively smooth sailing (you'll find enough tutorials on how to do this if you Google it). Another thing to note is that as of late, the team has not issued any updates/bug-fixes, something that might be a red flag.

Im not convinced Lucas... that bottom toolbar looks like TextMate to me.

I agree with you on Sublime though, my go to editor. Brackets http://brackets.io/ is also a great open source alternative with package management similar to that of Sublime.