I'm an Atari 2600 programmer! Not a great one, but I do have one published homebrew game in assembly, have written a pretty decent tutorial about learning to do that, and have made several useful browser-based tools.
Browser based editor for Atari 2600 player sprites, including animation, code samples, and rudimentary import/export.
playfieldpal-bB / playfieldpal-bB-DPC / PlayfieldPal
Playfied graphic editors - the first two are for batariBasic (regular rez and DPC+ 88 lines) and the final is the original super clunky legacy editor that spits out the bits in ASM order.
A way to play around with Atari sound samples in real time
Put down simple riffs and loops and generate real batari Basic programs!
A gui for Thomas Jentzsch's tune2600 to find the closest pitch matches for your notes in the regular Western scales.
An introduction to programming the Atari 2600...not for the faint of heart or weak of programming skill. Some people have found it a useful gateway to this esoteric artform.
Stella Programmer's Guide
A local mirror of B. Watson's HTMLification of the canonical document on the internals of the 2600. I find it the most friendly format for this important reference.
An unfinished attempt to collect some of the collected wisdom, clever ideas, and best practices of the [stella] mailing list into one convenient and hopefully inspirational location.
do re Bb - the BASICs of Atari Music
A guide to making music on the Atari. The examples are in batari BASIC but the tuning and general notes apply to any attempt at music in the 2600.
Batari BASIC kernel-don't-panic
A handy chart for visualizing the "acceptable" set kernel_options options.
Random Terrain's batari BASIC Commands
The quasi-canonical site for all things batari BASIC
"Collect" Tutorial Index
A 2K assembly tutorial by SpiceWare.
The Dig! Stella Archive
MiniDig Stella Selections
The [stella] mailing list was a stupendously important resource for most Atari developers, and The Dig was a search engine for diving into its past conversations. The MiniDig features choice selection from the old days of the [stella] list.
DASM is, by-and-large, the officially sanctioned assembler for Atari 2600 programming. This page also has the semi-canonical Atari 2600 "Support Files" such as vcs.h and macro.h. (Also I can offer a local mirror of vcs.h and macro.h)
PCAEWin [local mirror]
Three of the most important emulators. Z26 has one of the best reputations for rock-solid emulation. Stella may have become the defacto standard. PCAEWin has a kind of difficult UI but offers unique features like an integrated debugger and record .AVI movies. Unfortunately, its official homepage seems to be gone, but I have the most critical windows .zip here for download.
Atari 2600 Technical Tiki
Dr Boo's Woodgrain Wizadry, this tiki/wiki contains technical information about the Atari 2600 game system.
A 2015 weekend Game Jam original game for the Atari 2600, with a computer opponent added in 2020. Two bears running around in the woods shooting remote control bullets at each other... interesting mix of offense and defense! Music by Oliver Getz, Art by Winnie Gong.
A philosophical joke game. The gods have demanded you roll a rock up a hill. Every time you fail, the rock is awarded a point.
vgames @ kirkjerk.com
Not entirely Atari-related, a video game page I put together over the years. I was one of the first people to put a classic-video-game-themed webpage up, in the early 90s.
Console Passion Retro Games
A UK based site featuring "Online ordering of Classic Games and Vintage Consoles. All the major systems and Japanese imports. Modification services, competitions and polls."