SBT Console is a TextMate plug-in designed to add a view at the bottom of a TextMate project window that allows you to type SBT commands like compile, test etc.
To start an interactive sbt session simply type sbt or sbt shell. Once started you can exit it at any time by typing quit (as you would in the terminal). If you just want to run a single command you can just type sbt compileetc.
Simply download the latest build from the Downloads page and add the SBT_PATH shell variable in Textmate.
Open a Textmate project and press ctrl+shift+1 and it will toggle the terminal. Now you can type in any SBT command and see the input in the console-view. cmd+shift+1 will toggle focus between the document and the console.
To start an interactive sbt session simply type sbt or sbt shell. Once started you can exit it at any time by typing quit (as you would in the terminal). If you just want to run a single command you can just type sbt compile etc.
SBT Console plug-in adds a preference tab where you can change the colors used to display errors/warnings etc.