I too was ATO member and OS4 betatester.
I did translations for some OS4.x components and iBrowse. Our ATO BiH coordinator oversaw translation activities and did proofreading and translations himself. The latest cd and ct files were provided to us by OS4 localization coordinator.
Cannot remember the exact tools we used (flaxcat, catcomp) - I could check my notes.
I am interested in helping, but I believe any coordination/sharing would have to be agreed at some higher ATO levels (at least for OS4.x). Also, I think you have to be running OS4 to be able to test the translations, and I am not sure how many OS4 users we have in this region?
For other pieces of software, I believe you can contact the developer directly.