I am an old-school RQ fan....from the pure Chaosium days....and I am excited about the new incarnation! My question, however, concerns combat. Does anyone know how the parry will be handled? I have not seen a treatment of it in the previews.

I eagerly await the new RQ!
There's mention of parry as a seperate action rather than a factor influencing attack in Preview 2, so it's difficult to see how it could be much different from before.
This doesn't help much, but I found three mentions of parry in the previews:

The first one, from the first preview, is seemingly contradictory. Combat is the same, but different (specifically simpler; less math), and it includes parrying.
The second one, from the second preview, lists "Reactions". Parry is one of them.
Regarding "Reactions", two main points: 1) when attacked a character usually gets the chance to react, and 2) a character has the same number of "Reactions" as "Combat Actions". Also, Reactions are not made during a character's Strike Rank, and there are four types: dodge, parry, dive for cover and free attacks.
The third one, from the fourth preview, merely states one cannot parry whilst in a Battle Fury.

I cannot remember if one could parry infinitely and always under the old rules, but it seems under these rules one may parry only a limited number of times per 5 second Combat Round and not at all under some circumstances.
The actually mechanics of Parrying are, however, still a mystery.

There is one more mention, under the weapons list, a Target Shield may parry ranged weapons.
I would expect the "usually" regarding reactions to mean that you can under normal circumstances. If helpless or unaware, there would be no reaction, or if you've already used the reactions allowed, (in a situation where you have two actions and reactions but a foe or multiple foes able to attack you at least three times.)
Under the original rules you were not allowed infinite parries. You selected two actions each round (attack/parry, spellcast/parry, etc.) When skills reached 100% the opportunity to split actions (attacks) existed as long as each action had at least a 50% chance of success.
Well RQ2 didn't actually state it, but it's implicit from other rules (splitting parries with skill > 100, 2 weapon use, etc) that it's 1 per round. Defense could be split between as many attacks as you wanted, however, but with a minimum of 5% per each such attack.

RQ3 says 1 attack and 1 parry per round up front, with the option to exchange 1 of them for a dodge.
I _like_ the low parrying AP axes and maces seem to have. In my games (with short combat rounds) I run things so that you can either attack or attempt a parry with something like an axe or a mace. It just isn't like a sword or a fighting staff you swing around to attack, attack, parry, parry...

For the longer RQ rounds it will work quite well that you can parry with your mace, it just won't be a good enough parry to stop a determined blow.

If you want to use a mace, get a shield as well. If you want to use a 2-h axe, wear heavy armour (like the viking axemen did) or just be so menacing (and fast) that no enemy want's to close to fight with you.