There are emulators and Software Development Kits (SDKs) available for the Psion Series 3 Classic, 3a, Siena, WorkAbout, Series 5mx, Revo, Series 7, NetBook and NetPad.
The SIBO emulators run under MS-DOS, and are available for the Series 3 Classic, Series 3a, Siena and WorkAbout.
The EPOC & Symbian emulators install as part of the Software Development Kits (SDKs), and emulate the Series 5mx, Series 7 and NetBook. A separate installation allows emulation of the Revo.
SDKs are available for C++, OPL, Java and Connectivity development.
If you are having problems downloading the SDKs and/or PsiWin from the Psion website you can order it here.
Quartz 6.1 and NetPad SDKs also available.