For using it with “your favorite IDE”, there are a few 3rd party projects targeting the most popular environments. Hopefully one of these is your favorite?
If you prefer Eclipse, Jantje’s Arduino Eclipse plugin supports Teensy. Here’s some links:
. http://www.baeyens.it/eclipse/Install.html
. http://forum.pjrc.com/threads/1474-Anyone-using-Eclipse-for-development
If you love Xcode (Mac only), the embedXcode plugin supports Teensy.
. http://embedxcode.weebly.com/
. http://embedxcode.weebly.com/download.html
. http://forum.pjrc.com/threads/169-embedXcode-Teensy-3-0-on-Xcode
If Visual Studio (Windows only) is your game, the Visual Micro plugin recently added support for Teensy 3.0. Here’s the link:
. http://visualmicro.com/page/Teensy-for-Microsoft-Visual-Studio.aspx
If you’re a command line minimalist who only gets slowed down by any GUI, a good makefile is probably all you need. After you install Teensyduino into Arduino, the sample makefile is in hardware/teensy/cores/teensy3/makefile (on a Mac, control-click Arduino, choose “Show Package Contents” and dig down a few folders to find “hardware”). The makefile has comments with advice about which directories from Arduino you need to save, and which parts you can delete.
All 3 of the IDE plugins are third party projects. They’re separate projects from Teensy. If you use them heavily, please show them some support.