- Neil Streeter's ZX81 Index is a great ZX81/TS1000 site; I'm in the process of working out which .P files we share and which are unique.
- ZX-TEAM homepage has some useful information about ZX81 projects.
- Retro Computer Museum is a great source for all retro computers.
- Software Farm tribute page
- Sinclair ZX81 support page
- TZX File format