Pretty quick following New Vegas' launch, Bethesda has released the New Vegas version of the GECK toolkit, a slightly modified version.
New Features Should allow modders to get right on it. Good stuff!
New Dialogue Editor
* View and construct dialogue in a tree structure.
* Link NPC dialogue nodes to other NPC dialogue nodes without requiring a PC node in between.
* Automatically propagate speaker-defining GetIsID conditionals to new nodes.
* Copy/paste links directly without having to look up the appropriate topic or worry about topic names.
* Built-in support for low-intelligence dialogue options.
Activation Text Overrides
* Ability to change a default message like (Activate Door) to (Open Door)