SeePsion
- Read, write directly Psion Base serial 3 with logical synchronization. For PC Windows 95, 98, NT.
- http://perso.orange.fr/dominique.coupleux/

Kylom
- Productivity software for Symbian phones.
- http://www.kylom.com/

Phil Spencer
- Popular shareware and freeware programs for the Psion 3a, 3c, Siena, Series 5 and Geofox-One machines.
- http://homepages.nildram.co.uk/~nicko/

Dynasys-Psion Solutions Provider
- Accessories for Psion WorkAbout
- http://www.dyna-sys.com

Konstantin Saliy
- Software for the S3a, programmers' FAQ and a Russian Psion page (Windows 1251).
- http://www.aha.ru/~kis/

The Psionics Files
- A project for collating information about programming the Psion Series 3 and 3a which is not in the manuals provided with the machines.
- http://www.davros.org/psion/psionics/