Devs provide more detailed information on and related to the spell points system, with a focus on potions. This took place in a Members Only thread about the recent GameSpy interview with David Eckleberry. Excerpts below.

Samera:

I do want to clarify that any potions that increase a person’s spell points for the day will be extremely rare as well as limited in their use per adventure. Despite modification, we are working to preserve the spirit of the D&D rest mechanic. We are not planning on having a situation where you can carry 20 potions in your backpack at all times and can drink them one after another endlessly.

Sporkfire:

In the overall concept, they can be compared, as Samera said. However, the important point here is that we don't have naturally regenerating mana in the game, as other RPG's do. Spell points are recovered in line with traditional D&D rest mechanics, and so any item that affects their recovery will have to fit in with that. This why potions that do affect spell points will be very rare and limited in the number of times you can use them per adventure. So, this is not mana that you can have an endless supply of, as long as you pack the right potions.