Mario Pesce's DataMission.co.uk site which has quite a number of useful resources on iSeries & Unix integration, as well as recently released GPL utilities. They're packaged in Craig's CMD.xml format, and in self extracting .exe files
The following site all offer Open Source/Free software. If I can determine the license used, that's shown in brackets, otherwise have a look for yourself. If you know of any other Open Source iSeries project (or if you run one yourself), please let me know so I can include a link here.
AS/400 Resources - Links, Services, Binary downloads, etc.
@riadne Software and their excellent CoolSpools400 spooled file conversion tool. It's a commercial product but reasonably priced and comes with a big array of functions. The home page is www.ariadnesoftware.co.uk and I've put together a mini review. Now at version 5 and even better value for money. We use their Communique email software as well; great stuff.
All the screenshots and graphics I've used here are courtesy of The Gimp www.gimp.org. There is a Windows port too.
The AS/400 terminal emulation seen in the screenshots is either tn5250 or more recently James Rich's excellent x5250, based on tn5250. James has also contributed a very thorough tn5250 HOWTO.