According to the product page, the Hero Edition includes a limited edition 8.5" statue of Cole, a replica of his sling patch, and a Super Voucher. The voucher gives players access to the Lightning Hook, Electrocution Grenade, Kessler skin, 24K Gold Amp weapon, a DC mini-comic of inFamous #1, and the game soundtrack.
Sony tends to compile all the retailer-specific DLC into its Super Vouchers, as we saw with Killzone 3, so it's likely that those items will be split among retailers once the official announcement comes.
The Hero Edition is listed for $99.99, and said to be releasing on May 24. This is strictly in rumor territory for now, but if true it's the first we've heard of a release date for the game.