The Pterodon Website describes plans for a new free add-on for Vietcong called Red Dawn. They offer the first screenshots from the project, and the downloads page has a gameplay video (thanks Frans). Here's the deal:

Vietcong Red Dawn is a new official add-on for Vietcong. The add-on was released throughout the United Kingdom with the cover DVD of today's issue of the PC Gamer computer magazine, and will furthermore be released with gaming magazines in other countries. Vietcong Red Dawn will be available for free download from the 25th of March 2005.

The add-on contains a new Vietcong cooperative campaign, new multiplayer maps, one new single player mission, AI bots for the multiplayer mode, and completely new theme music.