Links to other Atari 8-bit resources which may be of interest:

AtariAge Atari 8-bit Computers Forum

Hiassoft (TurboFreezer, High Speed SIO driver)

The Montezuma (SIO2BT, RespeQt)

Peter Dell (Jac!: WUDSN IDE for Eclipse)

MADS Assembler home page

The Altirra Atari 8-bit Emulator by Avery Lee

SpartaDOS X Upgrade Project

Lotharek (vendor of U1MB, VBXE, SIDE2, Rapidus, Stereo POKEY and more)

AtariBits (home of the 1088XEL)

The Brewing Academy (1088XEL vendor)

The SymbOS Z80 Multitasking OS

Wilson Mines Co. (large collection of 6502-related information)

Jerzy Sobola (huge collection of Atari schematics)