Screen

To launch screen (if you currently do not have any open session):

screen

To reconnect to existing session:

screen -r

To detach from current session:

CTRL+a d

CTRL+a c                    // create a window
CTRL+a CTRL+a         // switch window
CTRL+a n                   // switch to next window
CTRL+a p                   // switch to previous window
CTRL+a "                   // get the list of windows (you can navigate this list using the arrow key)
CTRL+a w                  // get a small non-interactive list of windows
CTRL+a A                   // give current window a name
CTRL+a K                   // kill misbehaving programs
CTRL+a [                    // enter copy mode
CTRL+a ]                    // paste
CTRL+a _;                  // stop monitoring the current window for 30 seconds of silence
CTRL+a M.                  // start or stop monitoring current window for activity
CTRL+a ?                    // display a terse list of commands

screen is also capable of logging to files.

You can split the screen to see 2 windows at the same time.
http://www.kuro5hin.org/story/2004/3/9/16838/14935
man screen