Sinclair ZX-81 back from the dead - Tony Smith writes about the availability of ZX81 DIY kits. - http://www.theregister.co.uk/2000/10/10/sinclair_zx81_back/
ZX81Kit .Com - A European supplier of the Sinclair ZX81 computer in kit form. Also contains useful information and links, and other ZX81 hardware is available. - http://www.zx81kit.com/
ZX81 kit - UK based sales and support of ZX81 computers in kit form, also related peripherals and books. - http://www.zx81kit.co.uk
Sinclair ZX81 Collection - Collection of original Sinclair ZX81 hardware, software and literature. Photos and description for each item. - http://zx81.atspace.com
ZX81 Forever - Pictures, newsletters and programs made with the ZX81, a 16kb rampack and a Timex 2040 printer. Updated monthly. - http://www.zx-team.de/andre
ZX80 hardware page - How to build your own ZX80 and ZX81. - http://home.micros.users.btopenworld.com/zx80/zx80.html
ZX81 'Caverns' Game - PC Remake - Author of the original 1980's 'Caverns' game offers a PC remake for download. Includes game history and instructions. - http://www.users.globalnet.co.uk/~mart03/zx81.htm
Obsolete Computer Museum's ZX-81 Page - Technical specifications and pictures of the Sinclair ZX81 with comments from other ZX81 owners. - http://www.obsoletecomputermuseum.org/zx81/
Sinclair ZX81 FAQ - Some common questions about the ZX81. - http://www.honneamise.u-net.com/zx81/zx81faq.html
Sinclair ZX81 Benchtest - Article from Personal Computer World by David Tebbutt. - http://www.nvg.ntnu.no/sinclair/computers/zx81/zx81_pcw0681.htm
ZX81 - Planet Sinclair - Information, photos and resources for the Sinclair ZX80, including a detailed account of its development extracted from Ian Adamson and Richard Kennedy's book "Sinclair and the Sunrise Technology". - http://www.nvg.org/sinclair/computers/zx81/zx81.htm
Zebra Systems, Inc. - Timex-Sinclair ZX81 computer kits for sale. - http://www.zebrasystems.com/zebrasystems/zx81/index.html
ZX81 Home Page - A ZX81 FAQ, emulator and software links. - http://www.honneamise.u-net.com/zx81/
ZX-TEAM - An active German Sinclair ZX81 users' group. Site offers information about the Sinclair machines and the group's activities, including news of forthcoming events, nn English and German. - http://www.zx81.de/