PsiWin 2.3.3 works with Windows 7
PsiWin 2.3.3 works successfully with the 32-bit version of Windows 7. I've used it with both a COM port and a USB-to-serial adapter.
In order to use the 64-bit version of Windows 7 you'll need to use a virtual machine such as XP Mode for Windows 7 Professional or Ultimate edition.
After about 9 years of supplying hundreds of SDK CD-ROMs to the Psion community I am no longer selling CD-ROMs.
Downloads now available
You can now download the SDKs from the downloads page.
However, if you are really having trouble locating or downloading the Symbian v.5 / EPOC R5 software development kits (SDKs) drop me an email and I may have one or two CDs still kicking around.