Yes, every time I raise/lower my hands to ready magic, I get "you've already used that magic once today." That isn't right, is it?
Also, there's no dual-wielding one-handed swords? I can't seem to equip a second sword, although they were not matched types.
Yeah, hitting M shouldn't actually cast the magic, only ready it, unless you've got the Morrowind Code Patch installed and checked the appropriate box, but in that case, the hands shouldn't raise or lower. Don't know what's wrong with your game.
You can only use certain powers once a day, including the unlock spell from the Tower sign. And nope, no dual-wielding in Morrowind. Sorry.