Urbannen said:
I agree that Spellcraft checks should be used. The Spellcraft skill represents a character's knowledge of spells, oddly enough. The PHB even gives the DC for identifying spells that have already been cast. If the character recognizes the spell, they should really be allowed to read the spell description.
That DC (20+spell level IIRC) is for spells already in place with detect magic, which will take 3 rounds to get a proper analysis.
15+spell level for if the characters actually see the spell being cast.
IMC it's moot anyway - I do allow players to look stuff up, but if their initiative comes up and they don't know what they are doing they hold: In this case:
Wizard PC: Oh, wait I know this, I know this!
Fighter PC: Well hurry the F up!
Monster: Claw, smash, bite!
Cleric PC: Well hurry up already!
Rogue PC: I pick the wizards pockets!

Wizard PC: *mumbles* components, range, balh blah*
Fighter PC: Come on dude!
Monster: Claw, smash, bite!
Fighter PC: AAAAARGH!
Cleric PC: I heal the fighter.
Wizard PC: Ah! Concentrate all your fire on the super star destroyer!
Cleric PC: Crap, the figther died!
Wizard: Hey, where's my wand?
Rogue PC: *botches Use Magic Device Roll* Kablam!
Ie., they are better off going by their instincts...
(part of the above was joking of course)
Rav