Thoughts on /SavingState
Initial proposal on desktop-devel-list.
XSMP, libSM, ICE, and libICE docs (PDF only)
Obsolete X11R5 SM spec (WM_SAVE_YOURSELF; we most likely want nothing to do with this)
freedesktop desktop file spec (used by autostart)
markmc's session management proposal from last summer. This proposal involved a whole new architecture, but much of the argument is still relevant.