Deep Informational Technologies (Deep IT) have built Transliteration for Mac OS (only). As you may have imagined already, this software does exactly what it says on the tin: it transliterates! That is, it maps strings of text from one writing system to another (e.g. from Greek alphabet to Latin).
Download it here!
Having used and liked this software, it was more than natural to contribute some rules for it. In particular, rules to transliterate Greek to Latin, and Ladino to Hebrew. From Transliteration 2.1.1 and on, these rules are included in the download and need not be downloaded separately.
The rules are built in an XML file in the PLIST format. Here you can find information about each set.
TODO: Armenian, Georgian