I have done a fair amount of work localizing various programs into the Serbian language. Here are some examples.
I maintain the official translations into Serbian of the suite of Mozilla tools. I have been officially involved in Serbian L10N for Mozilla since 2007.
The suite of Mozilla tools consists of the following rather popular programs: Firefox, Thunderbird, Fennec, as well as the derivatives, like SeaMonkey.
I maintain, or used to maintain, Serbian language L10Ns for several (about 30 or so) small to medium size programs.
My translations of open-source programs into Serbian are offered as a single git archive for peer review. Almost all of them have been pushed upstream, and are now part of their respective programs. Skype is a notable exception due to their translation policy.
I maintain unofficial Serbian translations for the popular voice-over-IP program Skype. These translations are not bundled with the official Skype releases. So, in order to use it, you have to download it and load it into Skype.
The files are given below. Choose any one translation you prefer. Check out the Skype Serbian page, too.
The files given above are intended for the Skype editions that have
version numbrers beginning with 4.1. These are referring to a
now-obsolete Skype edition. Still, I understand they are usable for
newer Skype releases just as well.
At some point, I'll get to update the files for the latest Skype
edition (which, at the time of this writing is 5). Watch the changes
to this page to see when that happens.