a good, free text/code editor on Mac OSX

TextEdit

TextEdit is a good text editor and TextWrangler does code and text.

nano, emacs, vim, pico...

...you should already have them installed. Launch Terminal, type any of the above, and hit enter.

I like jEdit. It has the best search feature I've ever seen. It is called hypersearch. The search returns a tree of links.

If you installed dev tools then Dashcode as a lightweight editor is really useful.

Another vote for Text Wrangler here.

TextWrangler's great if what you need is a Mac OS X tool. If you're seeking something cross-platform look at jEdit.

I like TextWrangler but only use it now for composing responses in my online classes. Toward the middle of my web interface class I started using Komodo Edit. I don't use anything else anymore, but all I have done is HTML and PHP.

If you require a mac gui, I'd suggest TextWrangler

If you're open to trying something different I'd check out emacs and vim (specifically MacVim). Both are very powerful and offer you a lot more than what you'll get in a gui text editor. But it's layers and layers deep. Both will have a big learning curve but it pays off.