There are two sources to better understand this topic: Shaykh al-Malki, and Moosa Richardson.
Source #1 Sh. al-Malki
Sh. al-Malki made an announcement concerning Zakaat ul Fitr after his Jumu’ah khutbah on Friday 26 Ramadhan 1432 (8/26/2011).
In it he said that he would be going to a particular store in Jeddah. And if anyone wanted to give him their money then he would buy the zakaat ul-fitr for them (on their behalf). Then the Zakaat ul-Fitr would be distributed (as food) to those eligible to receive it.
You can listen to the announcement; its near the end of the audio file at about minute marker [-26.35]. However, listening to the entire khutbah is really worth your time.
|Sh. al-Malki Zakaatul-Fitr and `Eed 26-08-2011||/%20CCC</code>|
Source #2 M. Richardson
The second source is by Moosa Richardson. He gives some details on paying zakaat through a representative. Read it here, Paying Money to a Wikaalah (Representative) for Zakaatul-Fitr.