The folks that made Duke Nukem 3D. They may be out of business now, but their site is still up and running.
Homepage of the EDuke32 port. If you want to know more about its capabilities, this is your stuff.
Host of this web page. Duke Nukem fansite with news and resources for Duke Nukem 3D and Duke Nukem Forever.
This is the place for any discussion on EDuke32, the HRP or any other Duke related topics. Especially interesting for people interested in retexturing/remodelling projects.
EDuke32 IRC Channel
If you want to chat directly with someone from the EDuke32 or HRP project teams, this is the place.
Duke Nukem Wiki: HRP
Info about the Highres Pack on the official Duke Nukem 3D Wiki.
SVN Download Guide
Information about how to download latest HRP snapshot from the SVN repository with the TortoiseSVN client.
"Duke Nukem 3D HRP: The Classic, Only Better"
Techgage article about the HRP by Rob Williams from November 16, 2012. Also features a video showcasing the first two shareware episode levels in HD.
Doom Highres Pack
Without Doom, there would have been no Duke Nukem 3D. Reason enough to mention Kurikai's great HRP project for id's legendary FPS here, too. Versions for
several popular ports (Doomsday, GZDoom, Edge, Risen3D) are available.