@walkero
Welcome to A.org :-D
If you're serious about developing for OS4, perhaps the best thing to do would be to contact Hyperion - some betatesters seem to have development tools :-o
Apart from that, there do seem to be various guidelines for writing programs that'll transfer to OS4 easily (obviously don't hit the custom chips, don't use undocumented DOS features etc) but as I'm not a programmer you'd have to see if someone else knows more.
