For those who find tmux a bit arcane and screen a bit too primitive, I've found dvtm+dtach to be an excellent terminal multiplexer and session manager.
Abduco is a dtach replacement by dvtm's author. From http://www.brain-dump.org/projects/abduco/ :
"abduco is in many ways very similar to dtach but is actively maintained, contains no legacy code, provides a few additional features, has a cleaner, more robust implementation and is licensed under a BSD style license"