D&D 4E Hirelings in 4e

[HarbingerX]

To specifically answer to OP's question, there are no rules for hirelings (or henchmen). The rules related to NPCs giving assistance in combat are on page 116 of the DMG.

The rules encourage you to keep the focus on the PCs by minimizing the use of 'allies' outside of story needs. The problem with hirelings is that it gives players more than 3 actions per round in combat, which can lead to 'non-hireling-owning' player boredom.

 

[Klaus]

I'm playing in a party of 6, we're now at 3rd level, and the human Paladin has a warhorse since level 1. The horse has been the most effective creature on the map, in no small part due to Trample. The paladin simply pulverizes minions with a single move action.