Chaozers' Assember Page - Contains tools, documentation and sources (includes, for example, a DBM player and the latest AsmONE and AsmPro). - http://www.algonet.se/~chaozer/assembler.shtml
Superior's Amiga Assembler - Sources for various graphic demos, intended as learning material for beginners. - http://www.algonet.se/~davsjo/amigaasm.html
Amiga University - Miscellaneous sources and examples, including all issues of "The Source" coders magazine. - http://www.amigau.com/c-programming/assembler.htm
Asm-Pro for Amiga MC680x0 - Information about assembler coding and demo-coding for Amiga range of computers, also useful for C(++). And home of Asm-Pro m68k macro assembler. - http://home-1.tiscali.nl/~solognt/