www.rzkh.de
If you are in need of some free time on an IBM AS/400 aka iSeries, i have been using this service from Holger Scherer in Germany for several years. It’s available at http://www.rzkh.de/ and from this point you can signup for free access to a limited set of as/400 resources. Additional resources are available if you choose to pay some addition fees. The intro page will look like this.
Once you reach the as/400 signon screen it should look like this. Insert your signon credentials and you will have access to a variety of development tools we use. Cobol, RPG ILE, C ILE, the qshell access to the integrated file services allows us to develop bash scripts, java apps and many linux/aix programs.
Websphere app server and other more expensive tools are available when you choose a paid plan and later os/400 versions. OS/400 V5.4 is standard.
For as/400 access from your apple, linux or windows system, the excellant tn5250j terminal emulator runs nicely and can be downloaded from here from sourceforge if you need it.
This emulator is written in java so you will need an installed java version 1.4.2 or later. You may choose to remap your keyboard as i find the ‘enter’ key to be wrong for me cos i’m used to the old 5250 green screen terminals where the enter key was always located at bottom right of the keyboard. 
If you need an emulator for linux systems, then this sourceforge link will take you to a home page that offers one. I have not tried it myself so, if you do, please report back on your findings.
Just found this link in an old IBM journal from a developer who has updated tn5250j
