Woodchip: no, it's dynamic. You have full range of movement during combat and only two limiting factors on skill use, the global coldown (1.5 seconds, runs while casting so only relevant on instant skills) and ability cost (usually mana, rogues have energy, warriors have rage)).
Casting means you have to stand still (not for instant castspells though) until a bar charges up, after it finishes the spell effect will take place. Most spells take about 3 seconds to cast. Channeling works a little differently, the bar empties while the effect is taking place. In both cases being hit interferes, for casting it sets your cast bar bck 0.5 seconds (so get hit twice on a 2s spell and it will take you 3s to cast), for channeling it takes 0.5s off the bar, meaning the effect doesn't last as long. All spells have a range (often 30 yards), and require hard Line of Sight (no scenery in the way). Most spells require facing as well (target can't be behind you) so in PvP people will try to make you fail your cast by dodging about. You CAN turn while casting, with arrows or mouselook. Keeping a bead on someone shouldn't be a real problem for a D3er once you get the idea
Straightforward melee is an autoattack you can turn on and off, but it isn't going to get you far damage wise without using some abilities. You pick the target, hit attack, and get in range. Your attack delay and damage-per-hit is based on the weapon, character stats can boost DPH. Attack-based skills either give you a free swing with a bonus effect or add an effect to your next swing. All attack based skills have a short range and facing requirement. Most pets (warlock and hunter classes have minions which you can command) have melee based skills you can use on their behalf, I think only the imp does not and he has a ranged spell.
That's about as well as I can sum up combat in an overall sense. If you want to know things like class roles, tactics etc, send me a pm and we won't clutter up the forum.
ps don't read the WoW forums, most of the people there are BNet kiddies that whine about things they don't understand
edit: let me know what name you take sheepdog, if you roll horde I can probably lend you a hand. If you roll alliance, I might consider not ganking you heartlessly :p
what's your MC progress looking like?
