With it right around the corner, I want to go over it so it's a smooth release.

Hard mode will take all the restrictions and changes that are applied to ironman, but opens up slightly by allowing hard mode players to trade and stake each other (can still buy bonds off of normals like ironman accounts can). There will not be a GE. Also, the Boss Slayer Shop will not contain Raids items, which means these items won't be imediately available.

Combat XP rate: x10 (normal x400, iron x40).
Skill XP Rate: x10-x20? (normal and iron x20)
Can only loot PK'd items from other hard mode accounts.
Emblems and blood money will be dropped by killing any type of account.
Emblems exchanged for coins at their OSRS BH point values (lower than normal mode).
Target kills will not drop additional emblems.
Blood money shop will be released at a later date when rewards are decided on.
Ult. or hardcore ironman icon.

Ironman Upcoming Changes (Applied to Hard Mode):
Ironman accounts can participate in the PK Raffle, but only for winning the rares (no BM).
Wilderness Barrows disabled.
Item equip quest requirements for Lost City, Monkey Madness, and Dragon Slayer.

Also something I still have jotted down, but I'm unsure whether or not these will be changed in time for hard mode.
BM shop (prices?): torso/avas/r-pouch, r/d defender; Barbarian Assault/Pest Control items: drops/zombies