Enjoying the game so far, but I've got a few questions that I can't seem to find information on with a web search.

Is there a way to dispel the magical darkness covering some rooms?

Is there a difference between Torches and Lamps?

Are there potions or other ways to deal with poison in the field aside from my Conjuror's healing spell? (Fighting Black Widows is extremely annoying)

AFAIK you can't dispel zones of darkness.
Torches seem a bit brighter and probably last longer than lamps.
Poison can be dealt with by visiting a temple, or by spells. Eventually you will learn one that can heal the entire party at once. It's only really an annoyance early on.

Darkness can't be dispelled, but at least in classic versions, casting a light spell (or singing a bard song) might be enough for you to get your bearings.

There are only two other ways of dealing with poison in the field that I am aware of:
* Cast the Magician spell Restoration (this spell is *really* useful; you will be using it a lot once you learn it)
* Use an item that casts a spell that cures poison (the Pureblade casts Flesh Anew, and the Staff of Lor casts Restoration)

(In later games in the series, there's Heal All and Divine Intervention, but those spells aren't in BT1, and are overkill if poison is all you're worried about.)

Edit: I forgot to mention: In the classic games, Lamps last longer than Torches, but there's otherwise no difference. (BT3 actually has another item that can act as a torch, but doesn't get used up.)