One of the big changes coming in patch 3.1 is the change to mana regen, and it has a lot of people pretty frantic. The last thing healers want is for their life to become harder, right? Well, Ghostcrawler hit the forums today with some clarification on the subject.
Base regen (which is an equation that factors in both Intellect and Spirit) will be nerfed by about 40%. This means the mana you would regen while just standing around doing nothing will be quite a bit lower than it currently is. However, in exchange, regen-while-casting talents such as Meditation, Intensity, Spirit Tap and many others, whille be buffed so your in-combat mana regen shouldn't be harmed very much. It'll essentially prevent you from trying to wiggle in and out of the 5 second rule for big regen ticks, while not terribly bothering your mana regen while you're actually doing things.