This is a little experiment I've been working on for a while to increase TextMate's interoperability with XCode and give it the features of a robust IDE, like XCode, without sacrificing the elegance.
In short, the result is code complete, visual code-hierarchy, etc. for languages like ruby, python, objective-c, javascript, etc.
It's in an alpha stage, but is quite usable and been shown to enhance productivity. If you'd like to grab a pre-release build before it gets rolled into the TextMate subversion repository, you can grab it here:
http://code.google.com/p/textmate-xcode-completion/
Use the XCodeMate mailing list for feedback / support, as listed on the website.
Thanks, Tim