>If a programmer tells you to use vim or emacs, tell them no. These editors are for when you are a better programmer. All you need right now is an editor that lets you put text into a file. We will use gedit because it is simple and the same on all computers. Professional programmers use gedit so it's good enough for you starting out.
Been suggesting Ubuntu+gedit+gmate to my friends who are starting with programming. It's better than the editor that ships with Windows (most in my geographic region use windows... like 99%).
Any text editor will be able to save .rb files; they're just plain text files. Also, you didn't say which OS you're on, but assuming you're on Windows, notepad++ is a good free editor.
It's sort of like textmate but also cross-platform, so in theory you won't have to learn another editor. I'd learn it myself if I wasn't already used to textmate.
You might as well skip past all the toys and get Emacs and start on the lifelong journey of understanding it. Vim might be worth looking at too, but it's not my cup of tea.
OS x or linux check out gedit. (http://projects.gnome.org/gedit/ Downloads on right side of front page.) Also available for windows, but notepad++ is a little easier to use if you are used to windows programs.
My setup on Ubuntu is as follows. I use a drop down terminal called Yakuake. It drops down from the top of my screen when I press F12. From there I can create a ruby document by typing
vim example.rb
You don't have to use or learn all of vims features straight away. I probably use 1% of it but I like it. :w to save, :wq to save and quit.
I mostly use TextMate (OS X) and GEdit (on Linux), but perhaps 1/4 of the time I use RubyMine because autocompletion and immediate flagging of syntax errors can help.
