On Shabbat preceding Rosh Chodesh, the time of the molad is generally announced in units of hours, minutes, and chalakim. However, minutes are not a traditional Jewish unit of time; rather hours are divided directly into 1080 chalakim. So why don't we just announce the molad in units of hours and chalakim? On the other hand, if the goal is to make it easier for people familiar with our modern time system to understand the time of the molad, why don't we go all the way and convert the chalakim into seconds. (One chelek easily converts to 3 1/3 seconds.)
So for example, the molad for Kislev 5771 could be announced as "4 minutes and 10 seconds after 9pm on Motzei Shabbat" rather than "4 minutes and 3 chalakim after 9pm".