Lowest level specific classes can train Meditation at a class gm.
Enchanter Level 4 (Max 252)
Magician Level 4 (Max 252)
Necromancer Level 4 (Max 252)
Wizard Level 4 (Max 252)
Cleric Level 8 (Max 252)
Druid Level 8 (Max 252)
Shaman Level 8 (Max 252)
Paladin Level 12 (Max 235)
Ranger Level 12 (Max 226)
Shadow Knight Level 12 (Max 235)
http://wiki.project1999.com/Meditation
divide your meditation by 12 (+2) = mana per tick(6s)
so if you have 120 meditation you'd get 14 mana per server tick while sitting. (even if you sit down 1second before the server tick, you don't have to be sitting for the full 6s)