The Old Persian cuneiform was used widely from the 6th to the 4th century BC, at the time of the flourishing Persian Kingdom. The most ancient inscriptions date from 521, the Darius' texts (there are also several inscriptions which are sometimes considered as written even before Darius, but their genuineness is not proved yet). All the symbols of the script were syllabic and could be read as combinations of particular sounds. Its main features were borrowed from the Akkadian and Assyrian cuneiform scripts, but the number of determinatives (symbols which did not have sounds but specified its meaning) was much less. Actually, Old Persian was similar to Akkadian only in graphics, but not in sound of symbols and their meanings.
The script was rather peculiar because the Persian language, with its inflections and prefixes differed greatly from other cuneiform languages - Semitic, as a rule. That is why cuneiform seemed rather inconvenient for an Indo-European tongue (e.g., sounds like [pu] had to be written with the signs pa and u), and in the 4th century BC, after Alexander came to Asia, cuneiform was gradually replaced by the Greek alphabet everywhere.
Languages which used the script:
Iranian (Persian, other minor languages
of the Persian Empire: Median, Bactrian etc.)