ConTeXt bundle for TextMate
You can [download] version 0.2 of Patrick's bundle.
Just double-click on the 'dmg'-file to mount it and then double click on the bundle to install it. Once it is installed, you can eject the dmg and delete all downloaded files.
Completion: You can type in \col and press 'esc' and TextMate will run through all commands that start with \col, such as \color and \column.
Environments: type in 'env' and press tab to get a \start.... \stop pair. You can now type in the kind of environment.
Included texshow: type in a command, such as '\color' and press tab, and you will see the kind of arguments the command accepts. Just tab through all the highlighted arguments and you will guess how it works.
Online help: Press Ctrl-H and you can download the html page from texshow-web for the command where the word is on.